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SA-II/2014

Science(Class – IX)

1. CleanAir —AShared Concern

2. Environment and Development —Lessons from the Hills

Open Text Material 2Sample Questions withAnswers 7Some Probable Questions with 8

Open Text Material 32Sample Questions 36

37

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withAnswersSome Probable Questions withAnswers

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CONTENTS

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THEME – 1

Clean Air — A Shared Concern

OPEN TEXT MATERIALAbstract

Human activities have put water and air in a bad stateLet’s save, freshen and conserve them before it is too late.

Clean air is vital for the existence and continuance of all living organisms on earth.Naturally existing mixture of gases in the atmosphere, comprising of mainly Nitrogen,Oxygen, Carbon dioxide and water vapours, provides excellent conditions to support andsustain life. However, this natural composition of air is getting disturbed due to variety ofhuman activities. Human activities related to mainly industry, vehicular emissions, burningof fossil fuels, accidental nuclear emissions etc. contaminate the natural air with undesiredcomponents resulting in air pollution. These components, called pollutants, are not onlyharmful for living organisms but also affect non-living things adversely. The situation isquite alarming, particularly in big industrialized cities. With worldwide trend of shiftingof human population to cities and their human desire to lead more comfortable life, theissues and concerns related to availability of clean air for survival are becoming a greatchallenge for everyone.

The present text attempts to help the reader comprehend the situation in a holisticmanner, identify the causes and effects of air pollution, examine and analyze the existingstatus, reflect, debate and generate ideas as to what actions need to be taken at individual,collective or governmental level to meet the emerging challenges.

The ContextThe atmosphere surrounding the earth is a mixture of many gases which, along with

the other conditions, makes it a unique planet for existence of life. Unprecedentedurbanisation and development during the past few centuries and many human activitieshave disturbed the natural composition of this atmosphere. It is unfortunate that the costof development is very heavy and is being paid by causing a severe damage to the lifesupport system in the form of clean air.

Picture : 1 Picture : 2Source : http://www.cartoonstock.com, Source : http://oneair.webs.com

http://oneair.webs.com


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The contamination of air with undesirable gases and particulate matter is called airpollution. The substances which cause pollution are called pollutants. These are eithergaseous pollutants like oxides of carbon, sulphur, nitrogen etc. or particulate matter in theform of dust, smoke, fumes or mist. A person living in a city with polluted air is likely tosuffer from one or the other breathing problem.

To sensitize people towards keeping the planet Earth non polluted, Earth Day, anannual event, is celebrated on April 22. On this day, programmes are held worldwide tosensitize people towards environmental protection. People are made aware that if they donot act collectively, the green clean environment will be only for the pictures.

Picture : 3Source: http://www.tumblr.net

Carbon dioxide is necessary for the survival of life on Earth as it is an essential rawmaterial for the process of photosynthesis and green house effect. This effect is essential tomaintain and keep the earth’s atmosphere warm to sustain life. But due to excessive burningof fossil fuels and other carbon containing fuels, there has been an excessive release of CO2in the atmosphere. The increasing CO2 levels in the atmosphere lead to excessive heatingof the earth’s surface. The heating results into a new phenomenon called Global Warming.Besides carbon dioxide, the other green house gases present in the earth’s atmosphere intheir order of abundance are; water vapour, carbon dioxide, methane, nitrous oxide, ozoneand chlorofluorocarbons.

The gaseous and particulate pollutants together cause further damage to life. Haveyou ever observed that visibility is very low during winters due to fog ? Smog is a mixtureof smoke dust particles and fog. This phenomenon increases during heavy traffic hours incities. The reason is that smoke emitted from the exhaust of the vehicles settles over fog inwinter and reduces the visibility.

We all know about the smoke laden fog, called smog, which surrounded the city ofLondon in the year 1952. It resulted in the loss of about 4000 human lives and manyothers suffering from serious breathing problems according to the available press reports.Even the cattle had been asphyxiated by the smog. The unfortunate accident gave a rudeshock to the Governments of different nations and the problem of air pollution took acentral stage.

The human lifestyle in many developed countries is also causing another serious problemin the form of depletion of ozone layer. The use of refrigerators and air conditioners, fire


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extinguishers, aerosol sprays like deodorants etc. results inrelease of CFCs and N2O in the atmosphere which is responsiblefor depletion of ozone layer. This results in ultraviolet radiationsentering the atmosphere unobstructed causing damage to allkinds of life on Earth.

Picture : 4Source : www.pnuma.org

Many organizations are coming forward to create awareness among the masses so thatwe leave a cleaner planet for the coming generations.

Early childhood is a critical period for the continued development and maturation ofseveral biological systems such as the brain, lungs, and immune system. Air toxics canimpair lung function and neurodevelopment, or aggravate existing conditions, such asasthma. Infants who were born premature or growth-retarded may be particularlyvulnerable to additional environmental insults.

Stage : Newborn Infant/Toddler Young Child School-age Child AdolescentAge : 0-2 mos 2 mos – 2 yrs. 2 – 6 yrs. 6 – 12 yrs. 12 – 18 yrs.

Lung Alveolar developmentdevelopment :

High respiratory rateIncreasing lung volume

Air pollution Respiratory deathrisks :

Chronic cough and bronchitisReduced lung function

Wheezing and asthma attacksRespiratory Respiratory-related school absencessymptoms

and illnesses**Air pollution exposure has also been more recently linked to respiratory symptoms and illnesses in early life includingcough, bronchitis, wheeze and ear infections.

Picture : 5Source : http://www.environment.ucla.edu/reportcard/


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Following bar graph shows results of National Family Health Survey about health ofchildren in various cities of India. What could be the reasons for ill health of the children ofNagpur as compared to Delhi or Hyderabad ? Which city do you think would have a cleanerenvironment for the children to be healthy ?

Figure : City Level Prevalence of Child Health Outcomes

0.25

0.2

0.15

0.1

0.05

0Chennai Delhi Hyderabad Indore Kolkata Nagpur

Mean of fever Mean of cough

Survey statistics : 1 National Family Health SurveySource: http://www.rchiips.org/nfhs/report.shtml

Following statistics show the status of air quality in metropolitan cities of India, a surveyconducted by Central Pollution Control Board :

Is there any correlation between the health of the children and air pollution of aparticular city ?Status of Ambient Air Quality in 12 Metropolitan Cities of India

S. No. Name of the City State 2011

SO2 NO2 PM10*

1. Agra U.P. 3 23 1552. Bangalore Karnataka 14 28 913. Chennai Tamilnadu 9 24 924. Delhi U.T. 6 61 2225. Gwalior M.P. 12 20 3116. Hyderabad A.P. 5 28 747. Indore M.P. 12 14 1328. Kolkata West Bengal 12 65 1139. Malappuram Kerala 2 5 30

10. Mumbai Maharashtra 5 33 11611. Nagpur Maharashtra 8 35 10812. Raipur Chhattisgarh 15 42 310

Note : Source : Data as reported by CPCB/SPCBs/PCCs/NEERI


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Data for 2011 is average of data available as on date (08.08.2012). National AmbientAir Quality Standard for Residential, Industrial, Rural and other Areas (Annual average)for SO2 = 50 microgram per cubic metre, NO2 = 40 microgram per cubic metre and PM10 =60 microgram per cubic metre. NA = No Ambient Air Quality Stations operating underNAMP in these cities during the period.

Annual average concentration in μg/m3

Survey statistics : 2Source: http://cpcbenvis.nic.in/airpollution/air%20data%202011-2007/2011/air2011.html

*“PM10 is the term used to describe tiny particles in the air, made up of a complexmixture of soot, organic and inorganic materials having a particle size less than or equal to10 microns diameter (10 microns is equal to one hundredth part of a millimetre).”

Air pollution, the 5th largest killer in India : Study

PTI Feb. 13, 2013, 08:35 P.M. IST

NEW DELHI : Air pollution is the fifth largest killer in India taking 6.2 lakh lives peryear and Delhi is among one of the five most critically polluted regions in the country, astudy by a US-based health institute has claimed.

The other four most critically polluted regions in the country are Ghaziabad, Gwalior,West Singbhum district in Jharkhand and Raipur, according to the study.

Source: http://economictimes.indiatimes.com/photo/18486442.cms

All this was about the damage caused to the animate world due to air pollution but thedamage to the inanimate world is also not less. Much of the tangible heritage is at a dangerof surviving for the coming generations to see due to acid rains caused due to air pollution.The oxides of sulphur, carbon and nitrogen released into the atmosphere from chimneys ofindustries and exhaust of vehicles react with water of the rains and oxygen from air toform acids. Dissolved acids make the rain acidic in nature. Acid rains are very harmful forboth, living and non living things. Acid rains damage crops, pollute soil and water, ruin theharvest, damage aquatic life and erode buildings.

The Taj Mahal is a white-marbled domed monument built between 1632 and 1654.Approximately three billion tourists visit the famed site every year. It is listed amongst the


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ten wonders of world but is turning yellow because of air pollution. Glass factories, rubberindustries, Mathura oil refinery and other industries of the neighbouring towns whichburn fossil fuels are responsible for this. These industries release soot particles and gasesinto the atmosphere. The soot particles turn the colour of the marble to yellow and thegases react with water to form acid rain which corrodes the marble of the monument. Thisphenomenon is also called “marble cancer”.

In order to prevent further degradation of the building, the government has put a banon driving near the Taj Mahal. All cars and buses are parked roughly 1 km away. Battery-run buses or horsedrawn carriages have been set up for visitors to reach the monument.Industries in neighbouring towns are being persuaded to use cleaner fuels like CNG andLPG instead of coke in their furnaces.

The challenges and problems are complex and deserve to be addressed urgently.Immediate action points need to be decided and taken by every individual, social groupsand governmental level. Can you reflect, debate, discuss and decide these action pointswith your friends, parents, teachers and others to make a difference ?

SAMPLE QUESTIONS WITH ANSWERS

1. “Act local, think global”. How is this jargon suited to tackle the increasingproblem of air pollution ? Relate this to the marble cancer of the Taj and pollutionlevels in Agra city. Identify various steps that can be taken up at the individualand government level to curb the menace of air pollution.

Ans. Have you seen someone smoking cigarette. You can feel the smoke from metresaway. This gives an example that an action is local buts its impact is felt at a distance. Thisis what is happening in Agra city and nearby areas. The people are running small scaleindustries that release smoke. There are many other factories and industries like rubberindustries, glass factories, oil refineries that exhale tonnes of smoke into the atmosphereday and night. Smoke is responsible for yellowing of the white marble walls of the TajMahal. The result is the Taj Mahal which is famous for its bright shines under themoonlight is fading away. Also smoke has SO2 as a constituent which is causative agentfor acid rains. This mild acid is dangerous for marbles as it corrodes the marbles.

In other words, we can say that the fossil fuels are burnt kilometres away but theireffects are seen at the Taj Mahal. Also these are our acts that raise temperature at locallevels and the average of the summative local temperatures worldwide is responsible formelting of ice at the poles which are thousands of kilometres away. So, we need to actproperly at the local level keeping in mind its global effects.

We can do the following :

(i) Relocate the industry and use eco-friendly fuels to run industries and factories.

(ii) We can use filter and precipitators in the chimneys.

(iii) Local use of coal should be banned.

(iv) Vehicles should be run preferably on CNG.

(v) Afforestation helps in reducing air pollution.


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2. Identify from the pictures and data given in the text, the diseases whichoccur in children of age group 6 to 12 and 0 to 5 due to air pollution. Analyse thegiven data and draw conclusion about health of children and pollution levels ofvarious cities in India. What are the steps which can be taken by the authoritiesand communities to check the same ?

Ans. The newly born children of 0 – 2 months and the infants of upto two years aredangerously vulnerable to respiratory problems as their rate of respiration is extremelyhigh. As they respire high, the intake of polluted air will be maximum, thus the highestthreat to the lungs.

The children of age group 6 – 12 years have their lungs in the phase of increasingvolume. If there are exposed to air contaminants, they become prone to chronic cough andbronchitis in the early age. Their lung functions are effectively reduced. They suffer fromwheezing and frequent asthamatic attacks. This is not all, their education is grosslyhampered as they remain no more able to join the school due to various respiratoryailments.

As per data, Nagpur is the most polluted city as it has the largest number of childrensuffering from fever and cold, while Hyderabad is the least polluted city. The environmentis more favourable for children in Hyderabad as it may have greater area covered undervegetation. Also, the government might have effectively regulated the conducts of theindustries so far as their waste disposal behaviours are concerned. Indore is a city whichdoes not support the trend as there is greater number of children suffering from fever thanfrom cough and cold. It simply means that the situation of cough is taking its most severeform in Indore giving rise to more fever patients.

The government and the community should do the following :

(i) Ban use of fossil fuel (diesel and petrol) in the city for heavy vehicles, use CNGto run vehicles.

(ii) Put a ban on the entry of heavy vehicle in the city.(iii) Parks should be attentively maintained and afforestation drive should be run in

the city and nearby areas.(iv) Relocate the industries and factories.

SOME PROBABLE QUESTIONS WITH ANSWERS

1. “Humans have paid heavy cost of development.” Which costs have theypaid ? Mention any five.

Ans. Some of the scars that development has inflicted on humans are as follows :(i) Depletion of Resources : Many of the resources are at the verge of depletion.

There are ample possibilities that some of these resources will not be available to thefuture generations.

(ii) Loss of Forests and Imbalance of Ecosystem : For the establishment ofnew industries and urban settlements, the forests have been fell down at a large scale.This has created an imbalance in the ecosystem.


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(iii) Increasing Pollution : Pollution is a by-product of development. Most of thepollutions whether it be water, air or soil or sound, are the legacies of industrialdevelopment.

(iv) Disintegrating Social Bond : Development has strengthened the tendencyof nuclear families; especially in the cities. It has become the compulsion for many toswitch over to this system. It has given rise to a relationship gap between the familymembers.

(v) Health Hazards : However, with the development medical sciences witnessedmany landmark achievements but it is true that various new diseases emerged owingto the changing environment and life styles. Increasing cases of asthama, eosinophilia,heart diseases and diabetes and vision problem in youngsters are examples.

2. “A thing which as such is useful, may become pollutant in anotherway.” Give five examples to justify the statement.

Ans. (i) Carbon dioxide (CO2) : As such carbon dioxide is used as a raw materialfor manufacturing their food by plants. But, when in excess in the atmosphere itbecomes culprit for causing global warming.

(ii) Pollens : Pollens carry fertilization in many flowering plants. In many plants,wind is necessary for carrying them from one plant to another. But, when the amountof pollens in air increases at a place, they cause allergic symptoms in many people.

(iii) Dust : We all know that dust particles play vital role in the formation ofraindrops. But when their amount increases in the air, they become one of the majorpollutants.

(iv) Fertilizers : When used in optimum quantity in nutrient deficient soils, theyincrease crop yield. But when used excessively they cause soil and water pollutions.

(v) Music Systems : When used at low pitch it is pleasant to listen songs but athigh pitch it causes sound pollution.

3. How can you say that presence of Carbon dioxide (CO2) is a must for thesustenance of life on earth ?

Ans. Food is one of the essentials for survival of the living being. The only life formsthat can manufacture food are plants. Plants provide food to herbivores on whichcarnivores depend for their food. But, what are the raw materials required by plants formaking their foods ? These include carbon dioxide, sunlight, chloroplast and water. Inabsence of CO2 plants can’t make their food. Herbivores will die out due to starvation.Carnivores who depend on herbivores can’t survive and finally the whole living systemwill be wiped out. Also the temperature on the earth will not remain favourable forsustenance of many life forms owing to the decrease in CO2 level.

4. “Development and degradation of environment go hand in hand.” Justify.Ans. For development, we depend on natural resources for raw materials. When we

exploit the natural resources, we in fact, disturb the natural state of balance. Forexample, when we need land for human settlements, many a times we have to claimit from a forest area. This leads not only to a decrease in natural habitat for wildanimals but it also lessens the rainfall. The soil becomes underprotected hence we maysee the cases of soil erosion. Trees and plants absorb CO2. The level of CO2 will increase


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resulting in air pollution. For another example, we take coal and petroleum. We know,we can’t imagine of development without energy resources. To give pace to thedevelopment we need more and more energy. When we burn coal or petroleum products,a number of pollutants are released causing air pollution. In the mining areas, soilpollution is seen. So, we can say that development and degradation of environment gohand in hand.

5. “Neither excessive nor minimum, it must be optimum.” How can you justifythis statement with regard to the level of CO2 in the earth’s atmosphere ?

Ans. We all have heard of the proverb “excess of anything is bad”. This is also truein the case of high level of CO2 in the environment. When it is high in concentration,it becomes a pollutant which has various ill-effects. One of its major ill-effects is globalwarming which puts threat to existence of various life forms in long run.

The decreased level of CO2 too will lead to various complications. Carbon dioxideplays an important part in vital plant and animal processes, such as photosynthesis andrespiration. So most life on land will come to an end. Also CO2 aids in the greenhouseeffect, keeping the earth optimally warm for sustenance of life. If it’s level comes down,the average global temperature may decrease and the earth may become more colderposing threat to many life forms.

So, it is right to say that neither excessive nor minimum, the amount of CO2 in theatmosphere must be optimum.

6. List any five domestic activities which contribute to the developmentbut pose threat to the air quality.

Ans. Some of the domestic activities that directly or indirectly contribute to airpollution are as follows :

(i) In rural areas people use woodstoves for cooking foods. This releases lot ofcarbon monoxide in the air.

(ii) We use paints to colour the walls of our home. We use deodorant, sprays etc.These chemicals have constituents responsible for air pollution.

(iii) People smoke cigarettes, bidis, hukkas etc. which also contribute to air pollution.(iv) On some festivals like Diwali and Holi people observe woodfire and burn fire

crackers that contribute to air pollution.(v) Backyard burning and burning plastics, tires, garbages etc. put toxic substance

into air.(vi) Refrigerators, air-conditioners and freezers are responsible for spreading CFCs

in air which deplete ozone layer.7. How are industries contributing to air pollution ? Name any five such

industries.Ans. Following are the ways in which industries contribute to air pollution :

(i) The main industrial activity that emits CO2 is the combustion of fossil fuels(coal, natural gas, and oil) and use of electricity which is indirectly responsible for airpollution.

(ii) Transport industry is responsible for producing carbon monoxide.(iii) Metal industries release lead in air.


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(iv) Big industrial boilers release nitrous oxide (NO2).(v) During various industrial processes particulate matters are released in air.

(vi) Thermal power stations release sulphur dioxide in air.Few such industries releasing air pollutants are : Cement industry, Transportation

industry, Power industry, Coal industry, Metal industry, Textile industry etc.8. What implications may be there if the level of CO2 goes on decreasing ?Ans. Following complications may emerge out due to decrease in CO2 level :First, some vegetations would disappear because there would not be enough carbon

in order to produce energy molecules which means they would not be able to have theenergy to grow, develop and divide. So, most plants would just die.

Second, there would be more radiations coming to the earth unlike anything beforebecause carbon dioxide in the atmosphere does help to block the incoming of radiation.All this means the environment would become hot and become unfavourable for manylife forms.

Third, since plants would decrease in number, there would be decrease in oxygen.There would not be enough oxygen for humans to consume, and turn it into carbondioxide.

So, the whole living systems will become vulnerable to the threat of extinctionsooner or later.

9. Ranjan, a class-IX student lives in a village. To participate in a nationaldebate. He visited Mumbai recently. He observed that the air was pollutedthere. What could be reasons of this observation ?

Ans. When he reached Mumbai, within few hours he felt there was an irritation inhis throat, nose and eyes. He saw trees standing along the roadside had a thick coverof dust on their leaves. The buildings were loosing their colour. They were fading away.The air was having soots that lessened the visibility. Due to haze the traffic was veryslow and it took him about one and half hour to reach the hotel where he had hisaccommodation. Many bikers had their nose covered with handkerchieves.

10. When do we identify the problems due to air pollution ?Ans. There are various symptoms which show that the problems are due to air

pollution.Irritation of the eyes, nose and throat and upper respiratory infections such as

bronchitis and pneunomonia indicate the increased amount of particulate matter in theair.

When rainwater flows into lakes and ponds and after few days the fishes startdying, it indicates acid rain, which has changed the chemistry of the water reserve. Theacid rain was due to increased amount of sulphur and other oxides in the air.

If the vegetations are damaged and some other living organisms are harmed, itindicates an increase in ground-level ozone.

If there are frequent cases of asthamatic patients and reproductive malfunctioning,it indicates an increase in carcinogenic pollutants in the air.

If the acidity of soil is gradually increasing, there is ample chance that the air ispolluted there.


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11. “Patients suffering from respiratory diseases are mostly from cities.”Justify the statement giving reasons.

Ans. We all know that we are affected by the environment we live in. Cities are thecentres of industrial activities where a number of industries are run either in the citiesthemselves or in the nearby areas. These activities attract people and they move therein search of employment and better living conditions. So, population in the cities areswelling up day by day. More people means more means of transport, hence more fuelconsumption and other things that cause air pollution. So, the industries accompaniedby huge population contribute to the air pollution and air in and around the citiesbecomes highly polluted.

Children and old age people are more vulnerable to the polluted air and becomeprone to various respiratory diseases easily.

On the other hands, in villages more or less natural vegetations are there which notonly filtrate and absorb the air pollutants but also supply enough fresh oxygen. So,people there are relatively safe from being affected by respiratory diseases.

12. Below are the data of annual sell of inhalers by Sigma Pharmaceuticalsin four metro cities during years 2008-2012.

Year Sell (in lakh units)Delhi Mumbai Kolkata Chennai

2008 50 70 20 402009 70 90 30 452010 70 95 50 402011 50 110 40 452012 30 120 40 40

Analyse the trend of air pollution in these cities and write a report.Ans. The sell of the highest number of units of inhalers in Mumbai shows that in

comparison to other three cities, in Mumbai, people are the most affected by air pollution.It also indicates that Mumbai tops in industrial activities. The data show that duringthe year 2008-2012 the pollution level kept on increasing in Mumbai. Hence moreindustries and more consumption of fossil fuel. Also we can infer that either thegovernment was not much concerned or the steps taken by it were not enough to curbthe increasing level of pollution. The number of vehicles on the road must have beenincreasing.

So far as other cities are concerned, in the last two years (2011-2012), Delhi haseffectively controlled the level of pollution. Kolkata which was the least polluted of thesecities has almost effective control over the situation. In Chennai too the level has notbeen aggravated. However, on one hand Chennai has the same level of air pollution asfive years ago, in Kolkata the level has almost doubled in the last five years.

13. In North-eastern Indian states, level of air pollution is minimum. Givereasons.

Ans. In India, its North-eastern part is hilly and covered with dense vegetations. Itreceives heavy rains. Due to its hilly terrain, the roads have not developed much. The


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road density in this area is very low in comparison to other parts of the country. Manypeople derive their livelihood from forests and they take care of vegetation cover andhelp government in its conservation.

One will find very few factors responsible for causing air pollution there. For example,the area is less industrialized. Also if we take account of the fossil fuel consumption inthe area, owing to lesser number of vehicles in comparison to other regions of thecountry, this area is not a big consumer.

These are the reasons that the North-eastern states of the country has lower levelof air pollution.

14. Does rain help in decreasing air pollution ? How ?Ans. The air pollutants are found in two forms—gaseous and particulate matters.

Oxides of carbon, sulphur, nitrogen etc. are examples of gaseous pollutants and soots,dust, pollen etc. are examples of particulate matters. These pollutants do not go thatmuch up in the sky and stay near to the earth surface causing a hazy cover all around.

When it rains, many of these gases get dissolved with rain drops and fall down onthe ground in form of rain water. This is also true in the case of particulate matters.The falling rain drops allow them to get sticked and fall down on the ground.

So, after a shower for two-three days, we can see the atmosphere clear and pollutant-free. Not only that, the dusts settled over the leaves of trees also come down to theground with rain drops.

Therefore, we can say that rain helps to minimise the level of air pollution, but hasanother facet too. The pollutants present in air now reach to the ground with therainwater and pollute the soil and water with their toxic constituents.

15. “Assigning a day to a cause, for example Earth Day and celebrating itwith pomp and show is becoming meaningless.” Do you agree ? Support youranswer giving reasons.

Ans. Merely observing a day for a cause does not approve of our concern about thecause. We are just formally celebrating the day. The next step we take out of the venue,is against the cause, when we feel comfortable in lighting a cigarette after spendinghours listening to the importance of the cause. This is how we are concerned about aserious global issue. And observing the Earth Day is not a different case.

On a fixed day, we become attentive to the issue and observe it with pomp and showand then forget it for the next year. The pledge and oath that we take, the prudencythat we show, the way we analyse the data related to the issue to mark the gravity ofissue, the commitment that we promise to keep during the observance of the Day areleft far behind within a few hours and we come back to our set routine works.

We, in fact, have no commitment, we really don’t intend to keep promises and weshow what we are not. This is the reason that the very purpose of observing the dayis beaten.

So, in my view, every person can do something to contribute towards the cause andof course we can. If these were our activities which led us to this grave situation, onlywe can make the situation revert to the normal. We need to act and not a promise toact. When we will act, there will be no need to observe a Day, otherwise, this observanceis meaningless.


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16. Mention five potential sources of carbon dioxide.Ans. There are both natural and human sources of carbon dioxide emissions. Natural

sources include decomposition of organic matter, ocean release and respiration. Humansources come from activities like cement production, deforestation as well as the burningof fossil fuels like coal, oil and natural gas.

Human sources of carbon dioxide emissions are much smaller than natural emissionsbut they have disturbed the natural balance that existed for many thousands of yearsbefore the influence of humans. Some facts about carbon dioxide sources are givenbelow :

• About 87% of human carbon dioxide emissions comes from the combustion of fossilfuels.

• In fossil fuel combustion, coal is responsible for 43%, oil is responsible for 36% andnatural gas is responsible for 20% carbon dioxide production.

• The three main sectors that use fossil fuels are—power, transportation and otherindustries. The first two produce 2/3 of global CO2 emission.

17. How will be green house effect impacted if the earth’s atmospherebecomes thin ?

Ans. Our earth is covered by a blanket of a mixture of gases. These gases help thesurvival of life forms on the earth directly or indirectly. These gases perform protectiveand supportive functions.

The balance of the gases in the earth atmosphere is optimum. Any increase ordecrease in the percentage composition of air will disturb the balance and pose a threatto the survival of various life forms.

So far as the thinning of the atmosphere is concerned the amount of heat that theearth receives from the sun and the proportion of it retained help to keep the earthwarm enough for survival and fluorishing of the life forms. Any thinning will beresponsible for lesser retention of the heat i.e. most of the sun’s heat will be reflectedback. This will make the earth to observe severe cold environment because the greenhouse effect will not be practically operational. Under the effect of severe cold, theexistence of life will become impossible.

18. Planet X has a surface which does not absorb heat from the sun andreflects it back. It lacks an atmosphere. Can greenhouse effect be imaginedthere ? Give reasons.

Ans. For earth, the sun is the ultimate source of heat and energy. On the earthsurface solar heat is received in form of short waves. A part of this energy is absorbedat the earth surface and the rest is radiated back into the atmosphere.

We all know that the surface of earth is covered by a blanket of mixture of gases.Carbon dioxide is one of the constituents of this mixture. It has the ability to trap theheat radiations. In other words, it keeps the earth warm enough to enable the life formsflourish here.

Now, if planet X has a surface not capable of retaining the heat from the sun thenit will experience extreme cold conditions. Also, since the planet lacks in atmosphere, ifit’s surface were retaining heat, due to lack of carbon dioxide, the long heat waves couldnot have been traped. So, it is impossible to imagine greenhouse effect on the planet X.


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19. Can there be greenhouse effect on moon ?Ans. No, as such there is no greenhouse effect on the moon. The reason is it does

not have enough atmospheric covering to retain the heat from the sun. The atmosphereescapes out because of moon’s low gravity. The three primary gases in the loweratmosphere are neon, helium and hydrogen in almost equal amounts. Small amount offew greenhouse gases like methane and carbon dioxide is there, but they can’t trap andretain heat.

There are few light atoms like helium that can receive enough energy from the solarheating, but they escape in just a few hours.

The moon surface experiences extreme temperature conditions. Temperatures on themoon are very hot in the day time, about 100 °C. At night, the lunar surface gets verycold and drops to about –173 °C.

So, in this situation it is impossible for moon to experience greenhouse effect.20. How is greenhouse effect helpful in farming in cold countries ? Explain.Ans. We know that there are some gases like carbon dioxide or methane etc. which

cause greenhouse effect on the earth. These gases not only prevent the extreme solarheat radations from reaching the earth surface but they also prevent the radiated heatwave from going back to space and thus keep the atmosphere warm to sustain variousplant and animal life forms. This phenomenon is called greenhouse effect.

In cold countries, the temperature is almost sub-zero. This condition does not favourthe growth of many agricultural or horticultural crops. So, they make use of greenhouseeffect to provide conditions favourable for such crops.

The farmers make certain artificial arrangements based on this concept. They makeglass houses which allow the entry of solar heat radiations and do not permit them toescape out from the closed space. In this way suitable conditions are provided to thedesired crop to grow and develop.

Remember, the extreme cold conditions still prevail outside the closed space in whichgreenhouse effect is being carried out.

21. Do weather conditions affect air quality ?Ans. Yes, weather conditions affect air quality. Wind helps in the dispersion of

pollutants. Rain can wash pollutants out of the atmosphere. Temperature inversions(the condition when temperature decreases with increase in height and vice-versa) actlike a lid so prevent dispersion of pollutants.

The seasonal change also has an impact on air quality. The level of pollutants varieswith the season. An increase or decrease in the intensity of light and temperature alsohas an impact of the level of pollutants. In cold weather when temperature is low, thedensity of air increases due to more suspension of particulate matter in the air. In thesummers when temperature is high, the smog is usually not seen. During rainy daysair contains lesser quantity of pollutants while in other seasons the concentration ofparticulate matter in air is relatively high.

So, it can be said that weather conditions also affect the air quality.


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22. What is air pollution ? How can you say that urbanisation is alsoresponsible for air pollution ?

Ans. Introduction of chemicals, particulate matter, or biological matter into air thatcause harm or discomfort to humans or other living organisms or damages the naturalenvironment is called air pollution.

When there urbanisation happens, the population in an area increases. These peopleneed more foods, cloths and other materials to live. To supply their needs, industriesgrow up due to which air is polluted.

Due to increase in population, there will be more consumption of fuels, hence moreCO2 and other gases will be emitted into the air. Also more people will need morevehicles for transportation that in turn use fossil fuels and pollute air.

Again, industries are the main components of urbanisation. From industries varioustypes of gases are released which cause acid rain. Due to urbanisation forests andagricultural lands are reduced. It has bad effects on air quality in the area. Urbanpeople use refrigerators, air cooler, perfumes etc. which produce CFCs that depleteozone layer and causes harm to the air. Urbanisation requires new dwelling houses.The construction works leave huge amount of dust in the air affecting its quality.

23. Ozone in upper atmosphere is useful but near to the earth surface, itis harmful. How ?

Ans. There is a protective layer of ozone in the upper atmosphere (stratosphere).When the solar radiations move towards the earth, the ozone layer filters out theultraviolet radiations and does not allow them to pass through itself. This way it providesa protective covering against UV-radiations.

If UV-rays are permitted to reach the earth surface they may cause great harm toplant and animal lives. In humans these may cause some throat irritation, coughs,breathing difficulty and skin cancers. It may even lead to premature death.

If ozone is present near the ground i.e., in the atmosphere, it may cause healthhazards and cause damage to vegetation types and some animal life too. This ozone isproduced due to chemical reactions involving air pollutants.

So, ozone in the upper atmosphere is useful while that near the ground is extremelyharmful.

24. Is agriculture responsible for releasing greenhouse gases ?Ans. Yes. The three most common gases emitted in agriculture are nitrous oxide,

carbon dioxide, and methane.Methane is produced when crops, livestock feed or manure decompose in absence of

oxygen. It accounts for about 50% of agricultural emission. The digestion of organicmaterials by livestock is the largest source of methane.

Nitrous oxide is a by-product generated by the microbial breakdown of nitrogen insoils and manures. Its production is high in cases where the nitrogen available in soilsexceeds the amount required by plants to grow.

Carbon dioxide is released from soils when organic matter decomposes in presenceof oxygen. The largest source of CO2 production in agriculture is the drainage.


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All these gases—NO2, CO2 and Methane are greenhouse gases. So, it is true to saythat agriculture is also responsible for releasing greenhouse gases.

25. Write about the human activities responsible for ozone depletion.Ans. Ozone in the upper atmosphere acts as a protective layer against harmful

ultraviolet radiations from the sun. Ozone is not created directly, but is formed whennitrogen oxides and volatile organic compounds mix in sunlight.

There are chemicals that destroy the ozone layer in the upper atmosphere. Thesechemicals include chlorofluoro carbons (CFCs), halons, and other compounds that includechlorine or bromine.

CFCs are used in air conditioners and refrigerators as coolants. They are also usedin sprays, perfumes and deodorants. They can also be found in accord cans and fireextinguishers. Some of the solvents used in the industries are also known to depleteatmospheric ozone.

It is the human beings who for their comforts produce these things and thus put theatmospheric ozone layer in danger.

26. How are old age people affected by air pollution ?Ans. As people grow old, their body becomes less able to compensate for the effects

of environmental hazards. Air pollution can aggravate heart diseases and stroke, lungdiseases such as chronic obstructive pulmonary disease and asthama and diabetes. Thisleads to an increase in the use of medicines, which costs much to their meagre reserveincome. Also they have to pay more visits to health care providers. They may need tobe admitted to the emergency room and may even die. Ozone and particulate mattershave the greatest potential to affect the health of older adults. Fine suspended particlesmay increase heart attacks and asthama attacks and development of chronic bronchitis.Ozone even at low levels, can cause respiratory diseases.

What pollution can do mild injury to youngster’s life, can turn into chronic and evenfatal infection for an older person. An older person has ‘dirtier’ lungs that may getfurther damaged and may lead to complicated respiratory problems.

Older people have reduced immune system. They become more vulnerable topollutants.

27. Roshan visited a hill station, after a gap of twenty-five years. He founda drastic reduction in the green cover in the area. What adverse effects couldthis lead to, regarding air quality ?

Ans. It might be possible that the industries in this area have been given licensefor mining and establishing cement factories.

The industrial activities might have lead to deforestation at large scale. Also, due totransportation needs, the use of vehicles might have increased that developed a severestate of air pollution in the area.

Pollution and deforestation might have tremendous adverse effects on the humansettlements. The crops and trees might be under threat. The pattern of precipitationmight be affected. People might witness increased cases of respiratory disease. Farmersmight be worst hit because there could be ample chances of land and water pollution.

The rain water might cause soil erosion in absense of vegetation cover. Due todeforestation, the wildlife might have become vulnerable.


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28. Shobha lived in a village. Her school was at a distance about 5 km fromher house. Her father used car to drop her to school. One day she realised theimportance of minimising the use of fossil fuels and decided to go to schoolby cycle. What adverse effects of using fossil fuels she had in her mind ?

Ans. Shobha is a well aware girl. She knows the importance of fresh and cleanenvironment for community and individual lives, both at the national and internationallevels. Usually due to presence of greenaries and other natural components the state ofenvironment is healthy, particularly the air in the village is more or less fresh. Thenumber of private vehicles can be counted at fingers. Also the consumption of fossilfuels is in the agricultural sectors and negligible in the other fields.

So, the level of air pollution is relatively low. For the last few months, Shobha iswitnessing some sort of changes in the environment on her way to the school. She feltirritation in nose, eye and throat. She has seen increased number of patients sufferingfrom asthamatic attack.

In the fields, she has seen how the horticultural crops like raddish, cabbage, beans,carrot, tomato, onion and food crops like soyabean, pea, wheat, corn etc. are catchingdiseases. Plants like cabbage, corn, raddish etc. are susceptible to SO2. Hence shethought that the content of SO2 in air has increased. Similarly, cabbage, pea, wheat,etc. are susceptible to fluorides. Hence, the quantity of fluorides has increased.

So, she concluded that the air is being rapidly polluted. Since, by using car she wasalso contributing to it, she decided to go to her school by bicycle.

29. Rashmi visited a mall to purchase a deodorant. She liked the fragranceof one after trying out many. She decided to take it. As she walked up to thecash counter, she read the label giving the details of the contents. Sheimmediately changed her decision and placed it back in the shelf. Can yousay why ? Name few other products that contain the same for which sheavoided deodorant. How is this content harmful ?

Ans. Rashmi is a watchful and well aware girl. She is aware of the harmful effectsof chlorofluorocarbons (CFCs) on the atmospheric ozone layer. By her action, she wantedto demote the use of CFCs thereby conservation of the ozone layer.

CFCs when reach the atmospheric ozone layer, react with ozone molecules andcause harm to the layer. This way CFCs make the earth surface and thereby the lifeforms on the earth vulnerable to the effects of harmful ultraviolet rays from the sun.

Ozone layer is useful to us in the way that it absorbs harmful radiations from thesun, which otherwise may cause damage to plants and animals on the earth surface.

Thinning of the protective ozone layer will allow UV radiation on the earth whichcan lead to more cases of skin cancer, cataracts, and impaired immune systems. UV-radiation can also damage sensitive crops, such as soyabeans, and reduce crop yields.

30. How is rise in CO2 level responsible for climate change ?Ans. Carbon dioxide levels in the atmosphere have passed 400 parts per million

(ppm) for the first time in the human history. The late 20th century warmth in theNorthern Hemisphere was unprecedented during at least the last 1000 years. It warnsus about the human impact on the climate.


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The emission of CO2 in large quantities by the industries and other means has leadto global warming. Global warming is responsible for climate change. Climate changeis already happening and affecting people and nature all over the world. Extremeweather events (extreme summers and winter, etc.), cloudburst, rainstorms and heatwaves are affecting biodiversity and threatening precious ecosystems. All this has putdecades of hard work and massive investments in nature conservation and sustainabledevelopment at risk. Following events are evident of the climatic changes :

• Rise in the sea level leads to coastal erosion and flooding during storms.• The disruption of agriculture in some parts of the world due to increased

temperature and water stress.• Severe stress in forests, wetland and natural ecosystem.• Change in mating time in some animals.• Change in seasonal patterns.• Change in precipitation pattern.31. Write any five gases/pollutants responsible for global warming. Also

write their sources.Ans. Carbon dioxide is a green gas that has had the biggest effect on global warming.

It is emitted into the atmosphere by burning fossil fuels like coal, gasoline and naturalgas. Humans have come to rely on fossil fuels to power cars and planes, heating homes,and running factories. Doing these things pollutes the air with carbon dioxide.

Other greenhouse gases emitted by natural and artificial sources also includemethane, nitrous oxide and fluorinated gases.

Methane is a major emission from coal plants and agricultural processes.Nitrous oxide is a common emission from industrial factories, agriculture, and the

burning of fossil fuels in cars.Fluorinated gases, such as hydrofluorocarbons, are emitted by industry. Fluorinated

gases are often used instead of gases such as chloroflorocarbons (CFCs).Particulate matters are also the pollutants responsible for global warming. These

come from industries as soots etc.32. The scientists have noted a change in the sea level and said global

warming was responsible for this. What do you think, why have they reachedat this conclusion ?

Ans. Various greenhouse gases like carbon dioxide, methane, nitrous oxides andfluorinated gases are responsible for global warming.

The sea is the main water body which gets water from rain, rivers etc. Due toexcessive amount of greenhouse gases in the atmosphere there happens an increase inthe global average temperature. Even a slight change in global temperature manybring about many dangers to the life forms on the landmass. One of such changes isthe rise in the sea level. The land has ice claded mountains all over the world. The polesare great reservoir of water in form of ice. Also there are great glaciers. When thetemperature rises, ice starts melting. Since all water almost finds its way to the sea, thelevel of the sea increases.


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This is why when the scientists witnessed a rise in the sea-level, they concludedglobal warming as the responsible factor.

33. How are farmers affected by global warming ?Ans. We all know how the global warming is responsible for change in climate.

Climate change and agriculture are interrelated processes, both of which take place ona global scale.

Global warming is projected to have significant impacts on conditions affectingagriculture, including temperature, carbon dioxide, glacial run-off, precipitation and theinteraction of these elements.

These conditions determine the carrying capacity of the biosphere to produce enoughfood for the human population and domesticated animals.

Any change in seasonal pattern makes the farming a job of making losses. The cropsare temperature sensitive. A change in temperature affects the yield of the crops. Thereare crops which need more water. If there happens drought due to no rain or lowerprecipitation, the crop is damaged and farmers are trapped in debt. Also when it rainscats and dogs, the flooding takes place and the farmers incur a heavy loss.

So, any change in climate owing to global warming affects the farmers heavily andthis can be seen at the global level.

34. Give any two uses of CO2 in our daily life. Also give the reasons.Ans. During the hot summer days everybody wants to relax in cool air and drink

cold water. The science has made this possible making devices like refrigerator and airconditioners etc. And the credit of cooling goes to carbon dioxide which is used ascoolant.

The beverages are flavoured and made refreshing. Such beverages are calledcarbonated drinks. Carbonated drinks attain these qualities when at higher pressure,carbon dioxide is mixed in them.

When held under high pressure carbon dioxide dissolves in water, and causes bubbleson our tongue as it forms a carbonic acid when we take a gulp.

Dry ice is solid carbon dioxide. It is frozen carbon dioxide with a temperature of–78.5 °C and melts into gaseous rather than liquid form to create the popular smokeeffect.

35. How is CO2 removed/depleted from the earth’s atmosphere ? Give anyfive ways.

Ans. (i) The greatest consumers of CO2 in the atmosphere are green plants. Theyuse CO2 as a raw material for making their foods through the process of photosynthesis.

(ii) CO2 present in the atmosphere gets dissolved in the ocean water.(iii) A large amount of CO2 is consumed in the production of sedimentary rocks such

as limestone.(iv) Carbon dioxide is also consumed in the production of fossil fuels (coal and oil)

from the remains of dead plants and animals.(v) Various industrial processes like making carbonated drinks, dry ice, fizzy drinks,

fire extinguisher etc. also use carbon dioxide.


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36. Do all greenhouse gases trap heat equally ? On which factors does thewarming potential of greenhouse gases depend ?

Ans. It is not so. Greenhouse gases differ in their ability to trap heat. Suppose 1 kgof each of methane and carbondioxide is released into the atmosphere today. After 100years, the warming effect of methane will be about 20 time more than carbon dioxide.Methane, chlorofluorocarbon (CFCs) and nitrous oxides are more potent greenhousegases than carbon dioxide.

The warming potential depends on the following factors :• The present concentration of the gas in the atmosphere.• The time for which the gas remains in the atmosphere before taking part in a

reaction or being washed out by rainwater.• The capacity of the gas to absorb the radiations and the wavelength at which it

absorbs the radiation.• Any other indirect effects. For example, methane will produce ozone gas in the

lower atmosphere and water vapour in the atmosphere.37. What is difference between air pollutants and toxic air pollutants ?Ans. Air pollutants too cause health problems but not the most serious ones. Toxic

air pollutants also called Hazardous Air Pollutants or HAPs differ from air pollutantsin the degree of seriousness of the effects.

Toxic air pollutants are believed to cause cancer or other serious health effects, suchas damage to respiratory or nervous systems. These may exist as particulate matters orvapours (gases). These include metals, particles, and certain vapours from fuels andother sources.

38. What causes indoor air quality problems ?Ans. Indoor pollution sources that release gases or particles into the air are the

primary causes of indoor air quality problems in homes. Inadequate ventilation canincrease indoor pollutant levels by not bringing in enough outdoor air to dilute emissionsfrom indoor sources. Also due to lack of proper ventilation intense air pollutant can’t becarried out. High humidity and temperature can also increase concentrations of somepollutants. Paints and wire coating release air pollutants. Use of wood-stoves and inventedgas space heaters are also responsible for this. Smoking inside the house also enhancesair pollutants.

39. How is air pollution affecting what we see ? Give examples.Ans. The impairment of visibility occurs due to the scattering and absorption of light

by particles and gases in the atmosphere. It is most simply described as the haze whichobscures the clarity, colour, texture, and form of what we see. The same particles whichare responsible for causing serious health effects, for example, sulphates, nitrates, organiccarbon, soot (elemental carbon), and soil dust can significantly affect our ability to see.We must have witnessed how visibility is decreased during winter seasons due to fogsand smog.

40. Why is air pollution near roadways a public health problem ?Ans. Exposure to air pollutants and their effects on health are much higher for

people living near busy roadways. It has been observed that children living in close


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proximity to busy roadways have poorer lung functions, higher occurrence of asthamaand more respiratory symptoms compared to those living farther away from such pollutantsources. The air around the busy roadways is rich in sulphur dioxide, soots, carbondioxides, oxides of nitrogen and other pollutants released by the large number of vehiclesthat use the road. One can easily observe a layer of dust settled on the leaf surfacesof the trees around the busy roadways.

41. Keeping in mind the air pollution level, what change would you suggestin the design of the roadside houses ? Do you find any relevance of this factin ancient Indian civilization ?

Ans. The roadside houses are the most affected by the air pollution. This is becausethey are nearest to the road. To minimise the effect following steps should be taken :

(i) The house should be built at a relatively higher platform.(ii) The window should be at heights more than normal from the ground level.

(iii) A row of bushy/leafy plants of the height of more than that of the windowsshould be planted on the roadside.

(iv) The entrance should open on the backside.(v) There should be proper netted cross ventilation which can prevent the entry of

dust.This type of housing design was popular during Harappa civilization. In Harappan

(Indus valley) civilization, the main entrance of the house opened in the backside streets.42. In what ways are CO2 useful to us ? Mention any five ways.Ans. Following are the uses of carbon dioxide :

(i) It is used in the manufacture of carbonated drink. The presence of carbondioxide provides slightly tart and tingly flavour that makes such beverages so refreshing.

(ii) It is also used widely as a coolant, a refrigerant and an ingradient in themanufacture of frozen foods.

(iii) Carbon dioxide fire extinguishers are often used to control electrical and oilfires, which can’t be put out with water. Because the gas is denser than air and doesnot catch fire, it spreads like a blanket over burning material and smothers the fire.

(iv) It also prevents substances from decaying.(v) Dry ice (frozen CO2 with –78.5 °C) melts into gaseous form rather than liquid

to create the popular smoke effects. You can see this effect in movie scenes.(vi) When held under pressure CO2 dissolves in water, and it then causes bubbles

on our tongue as it forms a carbonic acid as we take a gulp.43. What is smog ? How can smog be prevented ?Ans. It is the stagnant yellowish-grey mixture of smoke and fog that forms a dense

cloud in the sky near to the earth surface.Smog is mostly caused by cars. In most cities, smog is formed when chemicals in car

exhaust fumes react with sunlight.To prevent smog following can be done :

(i) We need to reduce the release of air pollutants. An anti-air pollution programmecan be run.


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(ii) By reducing our driving just once or twice a week, we can help reduce trafficcongestion and air pollution.

(iii) Using bicycles or walk to the nearby markets for your daily purchases.(iv) Keep up with regular maintenance and tune-ups, changing the oil, and checking

tyre inflation can improve gas mileage, extend your car’s life, and increase its resale value.(v) Refuelling your cars during cooler periods of the day or in the evening can

prevent gas fumes from heating up and creating ozone.44. Which individual efforts would you suggest to conserve atmospheric

ozone layer ?Ans. Although most ozone depleting substances are used in industry and commerce,

still we can make a difference.(i) The most effective way of protecting the ozone layer is to reduce or even stop

using ozone depleting substances (chemicals).(ii) We should prefer air-conditioners that do not use HCFCs or CFCs as refrigerants.(iii) We should regularly inspect and maintain our air-conditioning and refrigeration

appliances to minimise refrigeration leaks.(iv) We need to recover and recycle HCFCs and CFCs in air-conditioners and

refrigeration appliances when they are in service.(v) Replacing and retrofitting such equipments to operate on non-CFCs and non-

HCFs should also be considered.(vi) We need to encourage growth of plants that produce oxygen and discourage

deforestation.(vii) We can decrease/control release of high temperature steam/moisture to the

atmosphere.45. How can you say that children and infants are at greater risk than

adults to air pollution ?Ans. (i) Unlike adults, children’s and infant’s body, lungs, and immune systems are

still developing.(ii) Children have a faster breathing rate than adults and inhale more air pollutants

than adults do.(iii) They do more exercises means they breathe heavier and get more polluted air in.(iv) Children breathe through their mouths more (the nose can filter particulate

matter from reaching the lungs, the mouth can not).(v) Air pollution increases a child’s risk by reducing the respiratory system’s ability

to fight infection and remove foreign particles.46. Mention local and global effects of global warming.Ans. Due to global warming following local effects can be easily observed.(1) (i) Due to change in climate pattern like heavy or meagre precipitation, farmers

are badly affected.(ii) Due to change in temperature some sensitive crops are adversely affected and

their yield decreases.


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(iii) Extremities of the climate are observed i.e., heavy or less rain fall, high humidity,landslide. The cases of fog and smog also increase.

(iv) There may be genetic changes in wild plants and animals. The mating periodof many of the animals can change.

(v) Due to increase in sea-level, people living near sea-coasts are badly impacted.(2) Due to global warming following global effects can be observed :

(i) Rise in average global temperature.(ii) Melting of ice caps of the mountains world over, glaciers, ice at the poles is

speeded up.(iii) The sea-level is witnessing a rise that may pose threat to the cities at the sea-

coast.(iv) Also the existence of many of the island-countries is threatened.

47. Jacob, a class-IX student goes for regular morning walk. He appreciatesnature and observes the colourful lichen growing on the tree bark along theroadside. To his surprise, he observed these organisms growing more in numberfew years back but now reduced. What is the reason for the decline in thenumber of organisms ? How can this impact the local health ? What remedywould you like to suggest ?

Ans. A decline in the number of lichens growing on barks of trees shows that thelevel of contaminants like sulphur dioxide has increased in the air. Sulphur dioxidemostly comes from the burning of coal or oil in power plants and from smokes releasedby the vehicles. Sulphur dioxide exposure can affect people who are suffering fromrespiratory diseases. It can also irritate people’s eyes, nose, and throat.

We need to begin an awareness drive to convince people about the following harmfuleffects of air pollution :

(i) Save people from getting prone to allergies, heart diseases, cancer, etc.(ii) Save land and building from acid rains.

(iii) Use public transport means.(iv) Start a campaign to drive the industry away from the inhabited area.

48. If we respond to global warming, can it harm our economy ? Give yourviews.

Ans. No, it is not so. Infact, if we respond correctly it will save our present andfuture.

We need to strike a balance between responding easily enough to avoid major costlyimpact, and responding sometime later in order to avoid big, expensive steps. A healthyenvironment to live in, timely cycle of seasons, flourishing greenaries, fertile rain andmany other are the sources on which human’s welfare is dependent. We need to takecare of all our resources in order to secure a pleasureful life. If we don’t, these resourceswill have to go under adverse impact of global warming.

But, it will be better to take collective efforts globally to avoid the futility of theresult.


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49. What are the effects of air pollution on newborn and infants ?Ans. The foetus undergoes rapid growth and organ development and the material

environment helps direct these processes, for better or for worst.(1) (i) Environmental exposure can cause infants to be born premature or low

weight or with certain birth defects.(ii) These babies are far more likely to die in infancy, and those who survive have

high risks of brain, respiratory and digestive problems in early life.(iii) The impact of environmental exposure on foetal development may be far-reaching

and the developmental delays may influence the risk for heart disease and diabetes inadulthood.

(2) Early childhood is also a critical period for the continued development andmaturation of several biological systems.

(i) Exposure to air toxicity may impair lung function and neurodevelopment.(ii) It may increase the cases of asthamatic children.

(iii) Infants who were born permature or growth-retarded may be particularlyvulnerable to additional environmental toxicity.

50. Will all the impacts of the greenhouse effect be negative ?Ans. The effect of global warming and climate change will not impact every region

in the word or all species of life the same way. For example, a slight rise in temperaturein some of the colder parts of the world may create less hostile conditions for humanhabitation and improve conditions for agriculture.

Similarly, changing rainfall patterns may favour some species over others. However,favourable consequences of the greenhouse effect for some regions or species do notmitigate its overall negative global impacts.

The social, economic and ecological disruptions brought about by climatic changesworldwide are projected to greatly outweigh regional benefits.

The effects of drowning coastlines could lead to hundreds of millions of climaterefugees. A severe disruption of the world’s food supplies through floods, droughts, cropfailures and diseases brought about by climate change would trigger famines, wars andcivil disorder in many societies.

So, we can say that in the light of a few favourable consequences, the impacts ofglobal greenhouse effects are horrible to imagine.

51. In what respects enhanced greenhouse effect and ozone depletion aresimilar ?

Ans. Ozone depletion and enhanced greenhouse effect both are environmentalproblems. Both are the results of human developmental activities.

Ozone depletion is caused by CFCs (Chlorofluoro carbons) and halons (Cl and Br),industrially produced chemicals used in refrigeration, plastic making etc. Once in theatmosphere, these chemicals destroy ozone in the atmosphere, 20 to 30 km above theground. It is the ozone layer that stops much of the sun’s UV radiation reaching us.

Both the greenhouse effect and ozone depletion are due to chemicals released intothe air by people’s activities. Another similarity is that CFCs are ozone destroyer andgreenhouse gases.


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52. Does the ‘ozone hole’ have any direct relation with climate change ?Ans. No, ozone hole is not directly related to climatic change. When we say ‘ozone

hole’, we mean that there is a decrease in the layer of ozone gas in the earth’s atmosphere,which helps to shield the planet from the sun’s harmful ultraviolet rays.

The ozone layer becomes thinner because of chemicals that were once commonlyused in products ranging from spray cans to foam, furniture cushions and thenrefrigerants etc. A thinner ozone layer allows more ultraviolate rays to reach the earth,causing sunburn and skin cancer.

So, it has no direct relation with climate change.53. How does water vapour in our atmosphere contribute to global

warming ?Ans. Due to various developmental and other activities, the normal level of CO2 and

other greenhouse gases increases in the atmosphere. This increase makes the earthwarmer. With the rise in temperature, the amount of water vapour rises in theatmosphere. Since water vapour in itself is a greenhouse gas, it further aggravates theprocess of warming. Water vapour actually magnifies the warming caused by excesscarbon dioxide and other greenhouse gases.

In this way an increase in water vapour contributes in global warming.54. How are the old age people impacted by air pollution ?Ans. As people age, their bodies are less able to compensate for the effects of

environmental hazards. Ozone and particulate matter have the greatest potential toaffect the health of older people.

Air pollution is a health concern for everyone, but even more so for the elderly asgenerally they have been alive longer, and have breathed in more pollution thansomeone younger.

The elders have weaker immune systems. It simply follows that as the body getsphysically weaker, so does all the other systems at work in the body. With the loss ofphysical vigour, hormone levels drop, healing takes longer, and the immune system willstruggle with bacteria that it once despatched with ease.

Also, the age and the weakening of the body’s ability to filter out and dispose offair pollution let other diseases affect both the heart and the lungs. So when there is anincrease in air pollution these diseases put elder people in the worst situation.

55. How is air pollution harming monuments in Delhi ? Explain.Ans. The recent surveys show that the historical buildings (which include monuments

and religious structures) located in the city are threatened by the increasing vehicularemissions and other gaseous pollutants being emitted in the air. The main causes of thedeterioration of the buildings include—physical, biological and chemical.

While air pollution is counted in ‘chemical’ category, dust pollution is termed as‘physical pollution’. Both the types of pollutions are prevalent in Delhi.

The stones/lime/plastic/clay etc are the most affected due to bio-deterioration.So far as particulate matters (e.g. dust, soot, etc.) are concerned, Chandni Chowk,

where Red Fort is situated, has the highest particulate matter air pollution—about fourtimes the national average—for any place in the country.


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56. How is acid rain harmful for buildings and monuments ?Ans. Acid rain has a damaging effect on many objects, including buildings,

monuments, statues, and cars. The chemicals found in acid rain can cause paint to peeland stone statues to begin to appear old and worn down, which reduces their value andbeauty.

Its effects on modern buildings are considerably less damaging than the effects onancient monuments. Limestone and calcareous stones which are used in most heritagebuildings are the most vulnerable to corrosion and need continued renovation which isexpensive and time-taking. The damaging effect can be witnessed easily. The sparklingTaj Mahal is slowly fading away.

When an acid comes in contact with alkaline materials (like limestone etc), it causesan exothermic reaction that dissolves the materials and so erodes it. Acid rain erodesstatues and buildings. It would have to be a very strong acid in order to break downmetals though.

57. As an individual, what efforts can one make to contribute in theprevention of global warming ?

Ans. Being a member of global community, an individual is equally important tocontribute in fighting against global warming. Following is the list of efforts which anindividual can make reduce global-warming :

(i) Reduce the use of car or vehicles which use gasoline/petrol or diesel. Follow allanti-pollution norms for gas emission, use recommended lubrications includinggear oil, keep tyre properly inflated or air pressured.

(ii) Use public transport whenever possible.(iii) Buy locally grown or produced foods to reduce transportation of products from

outside.(iv) Use energy efficient home appliances like replacing old refrigerator of higher

wattage through a new one.(v) Defrost old refrigerators and freezers regularly.

(vi) Use outside natural air drying for clothes whenever possible in lieu of machinedryer.

(vii) Use fresh foods instead of frozen foods.(viii) Avoid heating home which is largely done through electricity, gas, burning

coal or oil.(ix) Reduce waste and recycle organic waste in garden, lawn after proper

decomposing.(x) Plant trees and promote green living to absorb carbon dioxide.

58. What individual efforts would you like to suggest so as to prevent acidrain ?

Ans. Following efforts can an individual make to prevent acid rain :(i) Fossil fuel emissions cause pollution and acid rain and are expensive and non-

renewable. Another great energy source is man power; consider walking orbiking to work or school.


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(ii) The tree will absorb some of the polluted air and put out clean, fresh oxygen.So, we need to plant trees and promote others to do the same.

(iii) The biggest step that we can take to prevent acid rain is to decrease ourenergy consumption. We need to close the lights when we leave the house andturn off computer/television and other electrical appliances not in use. Also weshould not make excessive use of heating or cooling systems.

(iv) Vehicles are a major contributor to acid rain pollution. By using public transport,car pools, bikes and even our feet, we can help reduce auto emissions thatcontribute in acid rain pollution.

(v) We must follow the norms/rules made to prevent excessive emission of sulphurand nitrogen oxides.

59. Mention some worrying indicators that indicate something serioushappening due to greenhouse effect.

Ans. Greenhouse effect is responsible for global warming. There are changes worldwidewhich indicate that something serious is happening.

In the last two hundred years the average global temperature has increased byabout 0.5 °C. Temperatures have increased in all seasons in the Southern Hemisphereand in spring, winter and autumn in the Northern Hemisphere.

According to scientists, the retreat of glaciers and the warming of the tundra permafrostare clear evidences of global warming and climatic change. Currently, there is a profoundloss of ice mass and mountain glacier retreat is occurring all over the world.

Antarctic Peninsula which has one of the greatest masses of ice is warming up.Since 1940, the average temperature in Antarctic region has risen by about 2.5 °C. Theice-sheets are melting down, the penguin population is decreasing and the plants startedblooming.

These indications are enough to show that something serious is happening.60. The following graph depicts the percentage of the people suffering

from fever and cough in five Indian cities.

0.25

0.2

0.15

0.1

0.05

0Chennai Delhi Hyderabad Indore Kolkata Nagpur

Mean of fever Mean of cough


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What is the trend of air pollution in these cities ? Give few possible reasons.How is the health of the people in these cities affected ?

Ans. Among these cities, Hyderabad is the least polluted city while Nagpur is theworst polluted. The other cities in order of their increasing level of pollution are : Indore,Delhi, Chennai and Kolkata.

The reason to reach to this conclusion is that the cases of cough and fever are morein Nagpur and least in Hyderabad and the other cities also follow this pattern.

The reasons of pollution may include high density of industries in the city or neararound the inhabited area, poor vegetation cover, a large number of vehicles runningon the road, etc.

Also the people of Nagpur is possibly most prone to respiratory diseases and thepeople of Hyderabad is relatively less prone to respiratory diseases. The cases of peopleaffected from various respiratory disease may have an increasing order in Indore, Delhi,Chennai and Kolkata respectively.

61. Look at the cartoon given below, carefully.

What message does the cartoon give ?Ans. Two things are very clear from the cartoon : First, the atmosphere is highly

polluted and second the degree of pollution is such that humans can not breath in, inthe open air.

This cartoon has an inherent futuristic message warning humans of the dangers ofincreasing air pollutions.

The cartoon warns us that if we continue with our activities of spreading air pollutantsin the air, the day is not far away when we shall have to carry fresh oxygen with usto breath in.

The small plant in a jar on the back of the man is representing the source of freshoxygen. The black cloud in the background is representing our insensitive behaviourstowards our environment.


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62. In the light of the following caricature, justify the statement that ‘whatwe show is not the same what we do’.

Ans. The given caricature comments on the futility of the Earth Day Summits. Thecaricature has two highlighted parts : one is depicting our acts of felling trees recklesslyand the other shows how fake we are in our efforts to save the trees.

The caricature in its totality depicts the wide gap between our acts and words.Every year we celebrate Earth Day to motivate people and the government to take

steps to save our environment and thereby our Earth. Crores of rupees is spent on theoccasion world over. But all this is of no avail. The reason being we are not true to ourwords. Behind the scene we are recklessly exploiting the natural resources to meet theluxuries of life but what we try to show is a lot of efforts towards conserving the natureand natural resource.

So, the statement ‘What we show is not the same what we do’ is justified.63. Below is given a table showing the state of gaseous pollutants and

particulate matter in the air in different Indian cities.

S.No. Name of the City State 2011SO2 NO2 PM10*

1. Agra U.P. 3 23 1552. Bangalore Karnataka 14 28 913. Chennai Tamil Nadu 9 24 924. Delhi U.T. 6 61 2225. Gwalior M.P. 12 20 3116. Hyderabad A.P. 5 28 747. Indore M.P. 12 14 1328. Kolkata West Bengal 12 65 1139. Malappuram Kerala 2 5 30

10. Mumbai Maharashtra 5 33 11611. Nagpur Maharashtra 8 35 10812. Raipur Chhattisgarh 15 42 310


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Which two of the above cities would you like to live in and which twowould you avoid ?

Ans. The main air pollutants in these cities are SO2, NO2 and particulate matter.Nitrogen dioxide mostly comes from power plants and cars.Nitrogen oxide is formed in two ways — when nitrogen in the fuel is burned, or

when nitrogen in the air reacts with oxygen at very high temperatures. Nitrogendioxide can also react in the atmosphere to form ozone, acid rain, and particles.

High levels of nitrogen dioxide exposure can give people coughs and can make themfeel short of breath.

Sulphur dioxide mostly comes from the burning of coal or oil in power plants. It alsocomes from factories that make chemicals, paper or fuel.

SO2 aggravates the respiratory diseases in the people. It can also irritate people’seyes, noses and throats. It makes it harder for the people to see long distances.

Particulate matters come from sources like dust, sea spray, construction work etc. Itincreases the frequency of asthama attacks.

Raipur is the most polluted city among these. It has relatively high concentrationof PM10, NO2 and SO2. It is followed by Gwalior. So, these two cities I would not preferto live in.

Malappuram is the cleanest of the cities followed by Hyderabad. These can bepreferred over the other cities to live in.


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THEME – 2

Environment and Development — Lessons from the Hills

OPEN TEXT MATERIALAbstract

Man’s ability and power to transform his environment through technologicaldevelopments has undoubtedly enhanced quality of living in many ways. The same power,if applied without rational thinking and understanding the consequences of actions, canalso cause incalculable harm to the environment including the man himself.

Recent Uttarakhand disaster on 16th and 17th June, 2013 speaks volumes aboutirrational human actions and unscientific approach in the name of so called developmentresulting in a great tragedy. The irreversible damage done to the basic components ofenvironment due to cutting down of forests, building roads for promoting tourism,unplanned structures, setting up industries and constructing hydroelectric plants etc. allcontributed to what mankind will never like to see again.

The need of the hour is to reflect, examine and understand the natural as well as man-made factors responsible for the misfortune. The present text intends to initiate debate andgenerate ideas as to what actions need to be taken on the part of individuals, social groupsand the government to strike a better balance between economic developments andenvironmental concerns.

The Context

The widespread devastation in the hills of Uttarakhand brought about by cloudburstsand sudden torrential rains was tragic. Thousands lost their lives, villages were washedaway, buildings crashed into rivers and those who survived lost everything they had. Between16 and 17 June 2013, the hills of Uttarakhand experienced intense rainfall (370 mm withina period of 24 hours) which is exceptionally rare, particularly in this month. The averagemonthly rainfall in this region for the month of June is 210 mm while in July and Augustit is more than 600 mm. This happened to be the highest ever single day rainfall in Junefor the state — the previous highest being 350.5 mm in 1970.

Many Reasons

The horrific disaster that struck Uttrakhand has been assessed as a mix of natural andman-made reasons. Although cloudburst and landslides were the main causes of this disaster,nature alone can’t be blamed for this unfortunate turn of events. Man has played anequal, if not greater, role in this disaster. Poor disaster management infrastructure, lousybuilding constructions, massive deforestation, erroneous agricultural practices on barrenhill slopes, unscientific road building and quarrying contributed to make this India’s worstflood disaster.

Natural phenomena can sometimes strike very hard and cause disasters if preventivemeasures are not taken or if some human activities have harmed the natural environmentor upset the balance of the ecosystem.


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Ecologists point out that the huge expansion of hydro-power projects to meet the growingdemands of the expanding state and construction of roads to cope with the lakhs of touristsin Uttarakhand compounded the scale of the disaster. The incessant construction work alsoresulted in increased surface flow and rise of river bed due to disposal of debris in therivers. There has been excessive deforestation in these areas to make way for constructionin the name of development. The given table is a pointer in this direction.

1 2 3 4 5 6 7

Almora Bageshwar Champawat Chamou Dehradun Haridwar NainitalHydel Hydel Hydel Hydel Hydel Hydel Hydel

Projects Projects Projects Projects Projects Projects Projects1 13 2 51 11 2 4

Reserved Reserved Reserved Reserved Reserved Reserved ReservedMining Mining Mining Mining Mining Mining Mining59.6 ha 13.87 ha 182.8 ha 115.8 ha 63.51 ha — 123.83 haForest Forest Forest Forest Forest Forest Forest

Diverted Diverted Diverted Diverted Diverted Diverted Diverted598.4 ha 478.3 ha 308.5 ha 1,766.7 ha 1,203.1 ha 5,176 ha 1,104.7 ha

8 9 10 11 12 13

Pauri Pithoragarh Rudraprayag Tehri Garhwal Uttarkashi Udham Singh TotalHydel Hydel Hydel Hydel Hydel Nagar Hydel

Projects Projects Projects Projects Projects Hydel Projects Projects13 62 19 23 42 1 244

Reserved Reserved Reserved Reserved Reserved Reserved ReservedMining Mining Mining Mining Mining Mining Mining

67.91 ha 34.08 ha 51.38 ha 29.56 ha 141.84 ha 724.69 ha 1,608.9 haForest Forest Forest Forest Forest Forest Forest

Diverted Diverted Diverted Diverted Diverted Diverted Diverted610.7 ha 1,281.6 ha 299 ha 1,522 ha 577.5 ha 145.1 ha 15,072 ha

Source: Down to Earth

One can observe from the data that in order to build 244 hydel power projects, about14,072 ha of forests have been cleared. The region thus became vulnerable to landslides.Also this displaced a large number of local people for whom the forests were a source oflivelihood. There have also been reports to say that a large part of the power that is generatedis lost during transmission. This raises a question on the effectiveness of these hydropowerprojects. A report commissioned by the Union Environment and Forests Ministry in May2012 had warned the centre against going ahead with 24 hydropower projects planned onthe Alaknanda and Bhagirathi river systems in Uttarakhand. It stated that the projectswould destroy 22 percent of the state’s forestland and affect the unique Himalayan ecologyalong one-third of lengths of the two main tributaries of Ganga.

It seems that no rules and regulations that were put in place in order to protect ecologicallyfragile regions in the state have been ever considered. There is no doubt that the regionneeds economic growth. But this cannot happen at the cost of environment. Data with theUttarakhand state transport department bears this out. The state has seen a 1000 per centincrease in vehicular traffic in the last eight years, with ecologists having forewarnedabout the correlation between tourism increase and the higher increase of landslides.Uttarakhand ranks eighth among all states on the tourism map. This is one of the most


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fragile regions suffering from poor soil stability. Instead of looking at solutions to this problem,we have seen mushrooming of more and more construction in this area.

According to media reports, when the floods struck, about 28 million tourists were visitingthe state, while the local population is close to half that number. It is irresponsible to letsuch a huge volume of human traffic into an ecologically sensitive area, that too in themonsoon season.

“What else does one expect from the mountain if there is heavy tourist rush at vulnerableareas. The Himalaya is a young mountain and you dynamite it to build roads. Landslidesare bound to happen,” says a senior officer of Dehradun Meteorological Centre.

Yamunotri Gangotri Kedarnath Badrinath240% 250% 378% 136%

Increase of tourists Increase of tourists Increase of tourists Increase of touristsfrom from from from

2001 to 2012 2001 to 2012 2001 to 2012 2001 to 2012209,753 252,783 323,867 489,924

Pilgrims in 2013 Pilgrims in 2013 Pilgrims in 2013 Pilgrims in 2013till June 20 till June 20 till June 20 till June 20

Source : Down to Earth

Lack of Facilities

There were no warning systems in place, no weathering monitoring systems near themajor pilgrimage centres which saw a large number of tourists year after year. There donot seem to be any rain-gauges at Kedarnath and Badrinath and hence one may neverknow how much rainfall fell at those sites and we will never have full scientific explanationof what happened on June 16-17.

The floods washed away entire villages and small towns and destroyed entire roads,cutting off large areas, as well as homes, hotels and pilgrimage sites.


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Much of the infrastructure in the affected areas — roads, bridges, dams and civic facilities— have been completely destroyed or damaged.

Name of the No. of No. of No. of No. of No. ofaffected villages persons casualties houses animalsdistricts affected missing damaged/ died

washedaway

Rudraprayag 60 10,000 The causality 700 Approximately

Chamoli 39 2,500 due to the 130 9,500 animals

Uttarkashi 28 3,000 disaster is 160 killed.

Tehri 15 — 1056 as 60

Pithoragarh 10 100 reported by 25

Bageshwar 8 — Govt. —

Almora 8 — —

Dehradun — — 1

168 15,600 1,076

Human Help

The Army, Air Force, Navy, Indo-Tibetan Border Police (ITBP), Border Security Force,National Disaster Response Force (NDRF), Public Works Department and localadministration worked together for quick rescue operations. Several thousand soldiers were


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deployed for the rescue missions. Activists of political and social organizations were alsoinvolved in the rescue and management of relief centres. From 17 June to 30 June 2013,the IAF airlifted a total of 18,424 people — flying a total of 2,137 sorties and dropping/landing a total of 3,36,930 kg of relief material and equipment.

What Needs to be Done

The Administration is planning to enhance the monitoring of ecosystem with a focus onrecession of glaciers and their impact on river system in hilly areas. Strict rules are likely tobe enforced on the pilgrims and tourists as far as sanitation and garbage disposal isconcerned, for promoting the healthy environment at many holy sites scattered all over theHimalayas. People in the region also need to be prepared against potential disaster. Therehas to be a mandatory environmental impact assessment for the construction of all stateand national roads and expressways of more than a few kilometres in length, including thebroadening of existing roads. The most important precaution which needs to be taken isthat all hilly roads must have adequate drainage systems to fight with such naturalcalamities.

Uttarakhand disaster is a wakeup call for every planner and decision maker across thecountry. It is said that ‘those who do not learn from history are doomed to repeat it’. Thedisaster affected people from all across the country from different parts of the country, whowere on a pilgrimage to Uttarakhand.

We can’t stop natural phenomena from happening. But we can make them less damagingif we understand better why they happen, and what we can do to prevent or mitigatethem. Since people are partly responsible for disasters happening, we have to change whatwe are doing wrong, in order to avoid or reduce the impact of natural phenomena.

Every community must get to know its own features and surroundings: the naturalenvironment as well as environment built by human beings. This is the only way for acommunity to manage the hazards that surround it and to reduce its own vulnerability tothese hazards.

SAMPLE QUESTIONS WITH ANSWERS

1. A study by the PHD Chamber of Commerce and Industry suggests thattourism contributed to 30 per cent to Uttarakhand’s economic growth. Do youthink it will be a wise decision to ban tourism to this state ? Justify your answer.

Ans. The nature has endowed Uttarakhand with its all natural beauties like perennialrivers, snow clouded mountains, plenty of vegetations and other natural scenic ingredi-ents. These make it a tourist hot spot. As the data suggest, its economy has a greatercontribution from tourism industries. Lacs of tourists, both from the other parts of countryand from outside visit to enjoy the nature’s splendid gifts to the state. They enjoy rafting,trekking, adventure sports and many other activities. Uttarakhand is also known for itsreligious centres which attract millions of pilgrimages every year.

But, this industry has its negative sides as well. The tourists and pilgrimages leavetonnes of garbage after they return to their places. These garbages spoil the environment.A number of vehicles carry tourists in and out of the state and release pollutants in theair. So, the natural environment of the state is grossly affected.


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It is true that tourism, as an industry is a boon for the state but the price it is payingfor this is larger. It is the need of time to regulate the movement of tourists keeping in mindthe environmental health of the state. Emphasis should be on setting rules for practicesand activities for the tourists.

2. The Uttarakhand region’s key resource is the water that flows from highglaciers and mountains to the plains. This resource was utilized to build hydro-power projects that generate revenue for the state. How do you think this canbe utilized as an opportunity without being a threat to the ecology of state ?

Ans. One of the largest rivers of the world ‘the Ganga’, has its origin in Uttarakhand.There are many rivers that originate from the Himalaya and flow through the state. Thismakes the state one of the biggest water resource-rich states of the country. A number ofdams are built on these rivers to exploit hydel energy. This way the state has surplusproduction of energy which it uses to generate its revenue. But, damming poses threatsto the environment as it floods the vegetation cover that falls in its catchment area. Thedams are heavy structures built on the geologically unstable landmass. It attracts thedanger of earthquake. Over silting in river beds may cause floods.

It is true that the benefits of dam are tremendous and both the state and the countryas a whole rip the benefit of the resources but the resources need to be taken proper careof. The glaciers are melting that may lead to drying of water in the rivers. Vegetations aredepleting day-by-day so there is an immediate need of massive afforestation drive. Also weneed to conserve the existing landscape from further deterioration. And last but not least,we have to use electricity judiciously. If things are taken care of, the dams will not provea bane but a boon.

SOME PROBABLE QUESTIONS WITH ANSWERS

1. What is cloudburst ? Why does it take place ? How is it different fromrains ? What damages may it cause to the people ? Does it happen only in thehilly areas ? Why is it called cloudburst ?

Ans. Cloudburst is a sudden violent rainstorm falling for a short period of time limitedto a small geographical area.

The air currents rushing upwards in a thunder cloud hold up a large amount of water.If these currents suddenly cease, the entire amount of water descends over a small areawith a catastrophic force all of sudden.

The cloudburst is different from rain only in the amount of water that pours down onthe earth. Cloudbursts are usually associated with thunderstorms.

The cloudbursts may take place for few minutes but is capable of creating flood conditions.This leads to flash floods or landslides, house collapse, dislocation of traffic, damage to themeans of transport and communication and loss of lives and properties.

No, it is not necessary that it occurs in only hilly regions. However, they occur mostoften in deserts and mountain regions and sometime in the interior regions of continentallandmass.

It is called cloudburst probably because it was believed earlier that clouds were solidmasses full of water.


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2. Do you think man to be responsible for cloudburst ? Why/Why not ? InUttarakhand, thousands of people died during the recent calamity. To whatextent man is responsible for this ?

Ans. Cloudburst is a natural phenomenon over which man has no control. It happenswhen air currents moving upwards laden with dense clouds, suddenly stop. These currentsshade off all water that is received as cloudburst on the earth. Also, increased temperatureand hot summers in the plains lead to increased evaporation and subsequent cloud formationin the hills. So, as such we can’t say that man is responsible for cloudburst.

So far as recent calamity in Uttarakhand is concerned, the cloudburst and subsequentimpact was only the proximate cause. Human intervention has played a key role instimulating the natural antecedent of landslides occurring there. Human activities likeindiscrimate felling of trees, unplanned road building, mining and quarrying, raisingstructures at and around tourist hot spots and religious hubs are some factors thataggravated the fragile nature of the Himalayan zone.

Uttarakhand has been witnessing calamities for last several years, so the authoritiesshould stay extra alert but that did not happen and result was this great devastation.

So, we can say though man is not, as such responsible for cloudburst but is equallyresponsible for the calamity and loss that could be minimised by human efforts andalertness.

3. Do you think that it is our activities which, to a great extent, are responsiblefor frequent incidences of landslide in the hilly regions ? Give reasons.

Ans. Landslide is a natural disaster that brings loss not only of natural resources butalso of lives and property at a large scale. Mostly it occurs in deserts and mountains wheresoil is relatively loosely held. These regions constitute a fragile zone sensitive to humanactivities.

For development, humans do various activities and need various resources. Land is oneof these resources which they claim from the forests. They need land for building roads,raising structures for industries and institutions. So, they go for indiscriminate felling oftrees, construction, mining and quarrying. These activities make the sensitive fragile zonemore vulnerable.

When there is a heavy rain in the region, the soil having no support to bind with, startsmoving from its place. This results in the cases of landslides in the region.

Ill planned road building, encroachment by rural communities into forests, building ofdams and various other developmental projects spread even to steep hill slopes are all athreat to the unstable zone. Monsoon and cyclone induced rainfall makes the situationworst leading to landslides.

So, we can say that human activities are also responsible or provide conditions forlandslides.

4. Development of any area cannot be imagined without various constructionworks. Is it true for the hilly regions that construction works are responsible forlandslides ? Discuss.

Ans. For development of an area, various construction works are carried on. In suchareas, residential quarters, communication systems, water reservoirs, hospitals, business


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centres, schools, colleges etc. are built. All these loading activities disturb large volumes ofearth materials. This is added by new settlements for increasing population in the area.

As the human population and activities grow, they need more land cleared of forestsand other vegetables.

The trees that hold the soil in place are logged and burned for carrying out constructionsand other developmental activities. This makes the land vulnerable to heavy rains at theheights of hills.

When water flows down with high speed on the naked and loose slope, it invites theevent of landslide which causes great damage to the people’s lives and properties.

So, it can be said that various developmental activities e.g., construction works areresponsible for landslides in the hilly areas.

5. What can be the reasons of deforestation in the hilly areas ? Give any fivereasons.

Ans. These are various reasons for which deforestation is being carried out in the hills :(i) In the name of development, for making road, a vast tract of forest is being

cleared.(ii) Land is one of the essential factors for establishment of industries. For various

industrial set up trees are fell down.(iii) The greatest damage is done to forest tracts when dams are built on the rivers

in the hilly areas.(iv) Local people clear forests for agricultural lands.(v) For human settlements also forests in a large area are cleared.

(vi) Forest is harmed for obtaining timber.(vii) Various mining and quarrying activities are also responsible for loss of forests.6. To what extent are agricultural practices in the hilly areas disastrous ?Ans. The increase in human population has put a great pressure on land in form of

extension of crop lands. The hills are not exception to this fact.The need for increasing food production has been directly responsible for reduction in

the areas under forests and grasslands. This makes the unstable and sensitive soil massof the hills to slide down.

In the hills step farming is practised. However, this helps decrease the run-off from thenatural vegetation making the hill surface naked and vulnerable to the natural forces.

Shifting cultivation is the another agricultural practice in the hills that makes greatdamage to the vegetation cover and renders the relatively new soils of the hills andmountains to suffer in the hands of natural forces like cloudburst, storms, earthquakes etc.

So, extensive agricultural practices in the hills are also making them vulnerable tolandslides.

7. Write some natural factors responsible for landslides in the hilly areas.Ans. Following are the factors which independently or in combination with others

cause landslides :(i) Highly weathered rock layers or weak materials lying in hilly terrains. Stiff, dense

materials lying over soft materials provide conditions for landslides.


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(ii) Steepness of slopes helps in easy and quick sliding of debris, boulder, etc. down theslope.

(iii) The hilly areas having poor drainage are also vulnerable to landslides.

(iv) Loss of vegetation accompanied by water erosion of slopes enhances the chancesof landslides.

(v) Storms and cloudburst that produce heavy rains also provide conditions for landslide.

(vi) Earthquake may also trigger landslides in many different topographic and geologicsettings.

8. How and to what extent is deforestation responsible for landslides in thehills ?

Ans. Deforestation is the most significant of several man-made factors responsible forlandslides. It makes landslides more likely and flooding more devastating.

Trees and plants form the root systems in the soil. These roots act like net and arespread deep in the soil. These nets of roots help to hold the soil in place. The roots alongwithshade from the trees, also keep the soil moist and healthy so that it can absorb and drainlots of water.

The trees and plants check and decrease the speed of water falling from higher areasof the hills. Also they prevent the hill surfaces from direct hitting of rain drops. Thus theyhelp prevent the soil erosion.

In the absence of plant and tree cover, this cannot happen and the unstable soils ofthe hills and mountains will become exposed and result will be landslides.

9. How are mining and quarrying activities responsible for disasters in thehills ? Discuss.

Ans. The hills are relatively less stable. So, they are highly sensitive to various humanactivities. Mining and quarrying include active threats not only to the hills but also to thepeople and animal and plant lives in the area.

Unless proper precautions are taken, mining and quarrying activities significantlyharm the environment. Mining strips out the existing vegetation cover and by exposingthe surface to the natural processes like heavy rains, high winds, temperature and humidityalters the soil profile or the natural soil layers. Thereby the sensitive hills becomes morevulnerable to natural disasters like landslide and flash flood.

Once the natural vegetation is removed, erosion may increase dramatically and chancesof landslide increase. For quarrying blasts are carried that further destabilize the rocklayers. Open pits filled with water weakens the force that binds the rock. Also the debrisflows with run off into the water bodies causing silting thereby decreasing the waterholding capacity of the reservoir.

During heavy rains, water come down from the height and puts heavy pressure on thedestablized soil/rock mass resulting in landslide and mudslide etc.

So, mining and quarrying activities can be held responsible for disasters in the hills.


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10. How are people in the hilly areas affected by building of dams or hydro-power projects ?

Ans. The construction of larger dams completely changes the relationship of water andland, destroying the existing balance of ecosystem which, in many cases, has takenthousands of years to create.

Dams are meant to alter the natural flow of river and store water at a greater height.A vast tract of land is drowned and flooded rendering lacs of people devoid of their farmlands. Also thousands of hectares of forests are submerged in the dam water and cause lossof habitat to the wild animals. This way a dam often causes the greatest sustainedenvironmental impacts and man is equally affected by this.

Following are some adverse effects the people undergo due to dams :(i) Loss of agricultural land and thereby their livelihood.

(ii) Loss of forest and vegetation. People dependent on forest products for theirlivelihood are hit hard.

(iii) Loss of environment due to increase in water pollution due to stagnancy of damwater.

(iv) Flood caused due to over-silting of the rivers and reservoir.

(v) Increased vulnerability to landslide, earthquake, mudslide etc. like naturaldisasters.

(vi) Problems related to rehabilitation.

(vii) Spread of disasters like malaria, schistosomiasis, etc.

11. Roads are the basic infrastructure for development of an area. But inhilly area, it is proving a bane ? How ?

Ans. Geologically hills are relatively unstable. It is the demand of development thatroad networks be established for transportation of goods and people. Without proper andsufficient road networks, development cannot be imagined.

But, road building in the hills has proved an inducer for landslides. Cutting a road intosteep hillside weakens the slope above and increases the chance of landslide. When blastingis done to flatten the rocks, it accelerates the process of weathering of the rocks and releasesthe pressure of the rock joints. While making road in the hills, it is necessary to reinforceslopes weakened by the creation of road cut. Also, there is a need of retaining wall. Butthis practice is usually not followed. Thus the hills become more vulnerable to mudslide orlandslide.

The place where the road meets steep hillslide, hillslope stability is reduced due tovibration caused by heavy vehicles like trucks etc. The poor drainage along the road is alsoa culprit.

During building road, vegetation covers are removed, that further damages the bondingof the bedrocks. Any inducive factors like heavy rains, speeding huge run-off etc. in thatsituation, lead to landslide.

So, it is true to say the building road in the hills are becoming devastating.


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12. Hydro-power projects bring prosperity to the nation but pose manyproblems to the local people. Do you agree ? Give reasons for your answer.

Ans. (i) Dams are reservoirs of water. Water is collected at a height to tap its potentialenergy. Dams prevent river’s natural flow and thereby various economic activities of thelocal people, particularly the farmers and fishermen.

(ii) The flooding of large areas of land means a great loss to be natural environment.

(iii) People living in villages and towns that are in the valley to be flooded are displaced.They lose their farms and business.

(iv) The building of large dams can cause serious geological damage and render thearea unfit for habitation.

(v) Building of large dams leads to dampening of the nearby buildings, monumentsand other structures of historical importance.

(vi) The stagnant water in dams provide favourable conditions for disease causingorganisms (e.g., mosquito).

13. Power projects pose a threat to the Himalayan ecology. How ?

Ans. Following are the ways in which power projects pose threat to the Himalayanecology :

(i) Plants and trees that submerge in water begin to rot and release greenhouse gaseslike carbon dioxide and methane.

(ii) Building large dams destroys the living beings around them. Local life is disturbedas humans cannot live in such a flooded area and vegetations are destroyed. People livingin the locality have to displace.

(iii) Dams collect water for the production of electricity which alters the natural systemof water flow and deprive local people of their domestic water needs.

(iv) Making dams on rivers affects the amount, quality and temperature of water thatflow in streams which has drastic effects on agriculture and drinking water.

(v) The disturbed quality of water not damages only the reproduction of fishes but alsokills them.

(vi) Dams can disturb the mating seasons and mating areas of the water animals.

14. What are the impacts of huge human traffic on ecologically sensitiveareas in the hills ?

Ans. This is true that tourism brings economic prosperity to an area or a country butit has many adverse impacts too. These impacts can be direct or indirect. Direct impacts arecaused by the presence of tourists in the area while indirect effects are caused by theinfrastructures like roads, hotels, market place, restaurants, religious structures and manymore in connection with tourism activities.

The direct impacts of tourism on the environment of an area can be as follows :

(i) Impacts on soils(ii) Impacts on geological exposure


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(iii) Impacts on water resources(iv) Impacts on vegetation(v) Impacts on animal life

(vi) Impacts on the cultural environment(vii) Aesthetic impacts of the landslide

15. Are hydro-power projects boon or bane ? Evaluate.

Ans. India is a power hungry country with ever increasing demand of energy. As a fastdeveloping country, India needs huge supply of electricity to run its industries and forother domestic uses.

India has been using its coal reserve for thermal power but its exhaustibility compelsit to take resort to hydel-power in absence of developed technology for harnessing alternativesource of energy like wind, geo-thermal, solar, etc.

India is a country of rivers. So, it moved towards hydel-power. Many dams were builtand many are proposed. Hydel-power projects have both — positive and negative sides.

Positive sides :(i) Hydel-power is relatively less expensive.

(ii) It needs one time investment. There is less fear of the exhausting the resourceas water is continuously replenished in the reservoir.

(iii) It is pollution free.(iv) Relatively less expense on maintenance.

Negative sides :(i) Great harm to vegetation cover.

(ii) Rehabilitation of displaced people.(iii) Affects the livelihood of the local people.(iv) Flood due to silting of the reservoir.(v) Increases the risk of earthquake.

(vi) Increases the risk of landslide.

16. “Economic growth at the cost of ecology can’t be advocated.” Justify thestatement.

Ans. Economic growth is necessary for a country. But when it is achieved at the costof its environment and ecology, it becomes damaging in a long run.

We have numerous examples to show how harm to the ecology costs a country heavily.When ecology is disturbed, in fact, both the life and property are put in danger.

For example, to meet our energy needs, we make dams on the rivers in the hills. Forthis, a huge tract of forest and other vegetations is damaged. The natural flow of wateris disturbed to suit our needs. It is true that for our development we need to build dams,but they harm to ecology in numerous ways. There is loss of lacs of hectares of cultivableland and forest tracts that are drowned in the reservoir.


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The area becomes vulnerable to increased risks of earthquake and landslides. A numberof plant and animal species become endangered due to loss of their habitat.

Similarly, there are many growth related activities that cause a number of pollution —water, air, soil, etc. that harms our ecology greatly. The pollution induced by growth anddevelopmental activities greatly affect people’s health, brings about climatic changes,endangers plant and animal species.

If the harmful effects of spoiled ecology in long run is compared to the benefits ofgrowth activities, it proves an affair of great loss.

So, growth activities that harm the ecology cannot be advocated.

17. What are landslides ? Mention two natural and two human causes oflandslide.

Ans. (i) Landslides are the mass movements of rock, debris and soil down a slope ofland.

(ii) Natural causes of landslides : (a) When the hill areas with steep slopes becomesaturated by heavy rainfall, it increases the possibility of landslide.

(b) The earth has tectonic plates. When these plates move the soil that covers them alsomoves with them. In case of an earthquake in the areas of steep slopes, the soil steps downcausing landslide.

(iii) Human causes of landslides : (a) Hills are the major resources of mineral ores.Humans carry mining activities to obtain these. For unearthing them, they use blastingtechnologies. This causes other areas vulnerable to landslide, to slide due to vibrationsunder the soil.

(b) People, to obtain more timber, clear cut the trees that completely removes all oldgrowth timber from the area. This method is hazardous because it destroys the existingmechanical root structure in the area.

18. The mass removal of large trees and vegetation increases the chances oflandslide. Explain.

Ans. Vegetations are the greatest conservators of soil. In addition to their several otherbenefits, they also prevent us from the severe effects of various natural disasters. In thehills, particularly, when they are removed, the vulnerability to landslides increases for thefollowing reasons :

(i) Large trees provide strong root structures that penetrate fragile cracks in theunderlying bedrock and anchor the soil.

(ii) Old growth trees naturally have large leaf surface areas that cause much watertransfer. The water is drawn up from the soil and transpired out in the atmosphere. If theyare fell down, the rock surface comes under the weathering effects of water.

(iii) Forests create a canopy of foliage high up in the air to help dissipate rainfall overlarge area. If they are removed, water will fall in a small area and when imbibed by therocks will decrease their binding force leading to landslides.

(iv) Heavy wood-cutting machines damages soils and also cause vibrations in rocklayers that may lead to landslide.


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(v) Left over tree limbs or debris blocks natural drainage basin and leads to waterlogging which is one of the most important factors of landslide.

19. Make a list of damages caused by landslide.Ans. Following are some grave damages caused by landslide :

(i) Landslides are powerful destructive forces that declimate ecosystems. It wipesout man-made infrastructures and may cause a great toll to lives.

(ii) They damage the ecosystem.(iii) They cause loss of habitat that upsets the ecosystem.(iv) Animal and insect species are forced to compete for space.(v) May be that the debris flows into surrounding water supplying such as rivers

and streams and render them unfit for human consumption.(vi) They threaten to the habitat of aquatic species.

(vii) They damage farm lands and business activities.(viii) They contribute in the fall of the quality of the soil. When landslide happens, the

top soil is eroded and mixed with the speedily blowing debris.20. Write about some measures by local people/government to minimise the

effects of landslide.Ans. The effects of landslide can be reduced by taking following measures :

(i) Local government can reduce landslide effects through land-use policies andregulations.

(ii) Individuals can reduce their exposure to hazards by learning from previousincidents.

(iii) The surface water should be directed away from the site of landslide.(iv) By minimising surface irrigation the effect of landslides can be minimised.(v) The effect of landslides can be minimised by avoiding construction on steep

slopes.(vi) The effects of landslides can also be minimised by stabilizing the slopes.

(vii) Increasing vegetation cover can also help reduce the effect of landslides.

21. Once Jawahar Lal Nehru, our first Prime Minister said modern dams astemples. Today people are joining movements against making dams. One suchmovement is the Tehri Dam Movement. What do you know about it ? Why arepeople opposing this dam ?

Ans. It is the highest (865 feet) Indian dam near Tehri in Uttarakhand. It is meantfor irrigation and producing hydroelectricity.

The people are opposing this dam for the following reasons :(i) It is situated in seismically sensitive zone. It can bring earthquake in the region

and may cause unthinkable damage to the life and property, if damaged.(ii) It has submerged an area of about 52 square kilometres and displaced thousands

of people, who lost their livelihood and business.(iii) It can have severe environmental consequences being located in a fragile

ecosystem of the Himalayan foothills.


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(iv) It has lead to reduced flow of the river Bhagirathi. People have religiousaffiliations with this river (the Ganga).

(v) It has completely damaged the vegetation spread in a vast area.

22. You have visited an area which is prone to landslides. What measureswould you suggest to the people to take before the disaster to minimise therisk ?

Ans. (i) Collect information about possible landslide sites.(ii) Collect information about the area to which it may extend.(iii) Once identified, plant suitable trees in the landslide risk sites.(iv) Identify the warning signs of approaching landslide :

● stuck window or door● cracks on roads● leakage of water on slopes at the possible landslide site.

(v) If you have noticed any of the above signs, immediately inform the concernedauthority to take proper steps in time.

23. You are on a hill-tour. You have heard about approaching landslide. Whatwill be your safety strategies ?

Ans. (i) After I come to know about an approaching landslide, I will immediately switchoff electricity, turn off gas and water supply network.

(ii) Take my most valuable things (not bulky) and emergency kit and will get readyfor evacuation.

(iii) I will act according to the guidelines issued by the concerned authorities.(iv) If the landslide speed is low, I will not be in panic, if it is high then immediately

vaccate the place.(v) I will not forget to inform others about the approaching menace and also suggest

them what to do now.24. What is mud-flow ? When does it occur ?Ans. Mud-flow is a sudden flow of fine grained mountain sediments, big stones and

rock mixed with a large volume of water down a steep slope.Following may be the possible reasons for mud-flow :

(i) Intensive or heavy rains or cloudburst.(ii) It can also be caused by damaged dam, embankments and other hydro-technical

structures.(iii) It can also occur due to faulty engineering designs and seismic quakes.

25. What would you do when a flood is likely in your area and you must needto evacuate the place ?

Ans. (i) When a flood is likely in my area : (a) I will attentively listen to radio/TVnews bulletins.

(b) I have to be conscious of any flash flood. If I see any such possibility, I willimmediately move to a higher ground, I will not wait for any such instruction from theconcerned authority.

(c) I will keep myself aware of streams/drainage known to flood suddenly.


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Flash flood can occur in these areas with or without such typical warnings as rainclouds or heavy rains.

(ii) When I need to evacuate : (a) If time permits, I will secure my home, bring inoutdoor furnitures and move essential items to an upper floor.

(b) I will turn off the utilities at the main switches. Switch off the electricity and willnever touch the electrical appliances if I am wet.

26. What suggestions would you like to give for creating a sustainabletourism ?

Ans. Following measures can be taken for creating a sustainable tourism :(i) By regulating the number of tourists in certain areas, we can reduce the pressure

on natural environments caused by tourism.(ii) The promotion of alternative fuel saving technologies can help reduce the use of

firewoods by tourists and lodges.(iii) We must build authorised composites so that wild camping by the tourists along

the traits would be reduced.(iv) We should allow and promote local people to take part in decision making process

and at the same time increase the support and cooperation from the locals for theenvironmental protection projects.

(v) Uses of certain materials like polythene, heavy vehicles, plastic tents, plasticbottles etc. by the tourists and that are harmful to the environment, must berestricted.

(vi) There should be proper and strict regulations to prevent mushrooming of hotels,bars, restaurants, lodges etc. in the ecologically sensitive tourist or religiouscentres.

27. How are constructive works responsible for recent calamities inUttarakhand ? Give your views.

Ans. Uttarakhand is an ecologically sensitive region. The government has promotedtourism. In the last few years, the number of tourists visiting the region has become2.5 time.

To draw from the opportunity hotels, shops, houses, restaurants, etc. were recklesslybuilt. Thousands of acres of forests were cleared. These structures were built upon cavingroadside, steep slopes and on the flood plains of rivers.

Encroachment of these natural boundaries of rivers is posing great dangers. Alsoimportant government buildings like university, radio station, jail, schools, etc. are built onthe flood plains.

The hydro-power dams are the great threats. Making of these dams involve drillingtunnels in the hills by blasting rocks, placing enormous turbines in the tunnel, cuttingdown forests to build water channels, roads, townships and other infrastructures andlaying transmission lines by other destructive methods.

These make harms not only to the ecology but also destabilize the already geologicallysensitive region.

So, we can blame construction works for frequent calamities in Uttarakhand.

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Based onBasedon CBSE OTBA OPEN TEXT BASED ... · OTBA : SCIENCE – IX / 1 e B o o k RELIABLE ENTERPRISES OPEN TEXT BASED ASSESSMENTOPENTEXT BASED ASSESSMENT SA-II/2014 Science (Class