The sectoral trends of multigas emissions inventory of India

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Atmospheric Environment 40 (2006) 4608–4620

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The sectoral trends of multigas emissions inventory of India

Amit Garga,�, P.R. Shuklab, Manmohan Kapshec

aUNEP Risoe Centre, P.O. Box 49, DK-4000, Roskilde, DenmarkbPublic Systems Group, Indian Institute of Management, Vastrapur, Ahmedabad, India

cMaulana Azad National Institute of Technology, Bhopal, India

Received 11 November 2005; received in revised form 16 March 2006; accepted 24 March 2006

Abstract

This paper provides the trends of greenhouse gas (GHG) and local air pollutant emissions of India for 1985–2005. The

GHGs covered are six Kyoto gases, namely carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), perfluorocarbons

(PFCs), hydrofluorocarbons (HFCs) and sulfur hexafluoride (SF6). The local air pollutants are sulfur dioxide (SO2),

nitrogen oxides (NOX), carbon monoxide (CO) and total suspended particulates (TSP). These estimates incorporate some

of the most recent scientific assessments for India.

The multigas emissions have varied sectoral and fuel-based dominance, as well as regional distribution patterns. Coal

consumption in power sector dominates CO2 and SO2 emissions, while power and road transport equally contribute to

NOX emissions. Rice cultivation and livestock-related emissions from the agriculture sector dominate CH4 emissions, while

synthetic fertilizer use in the same sector is the major source of N2O emissions. PFC emissions are dominated by C2F6 and

CF4 emissions from aluminum production. The majority of HFC emissions are contributed by HFC-23, a by-product

during the production of HCFC-22 that is widely used in refrigeration industry. CO emissions have dominance from

biomass burning. Particulate emissions are dominated by biomass burning (residential sector), road transport and coal

combustion in large plants. These varied emission patterns provide interesting policy links and disjoints, such as—which

and where mitigation flexibility for the Kyoto gases, exploring co-benefits of CO2 and SO2 mitigation, and technology and

development pathway dependence of emissions. The present inventory assessment is a pointer to the future emission

pathways for India wherein local air pollutant and GHG emissions, although connected, may not move in synchronization

and therefore would require alignment through well crafted development and environment strategies.

r 2006 Elsevier Ltd. All rights reserved.

Keywords: Multigas; Kyoto gases; Emission trends

1. Background

Industrial development has contributed signifi-cantly to economic growth in India over last few

e front matter r 2006 Elsevier Ltd. All rights reserved

mosenv.2006.03.045

ing author. Tel.: +45 4677 5169;

999.

esses: [email protected] (A. Garg),

.ernet.in (P.R. Shukla), [email protected]

decades; however, development has not been uni-form. Wide sectoral and regional variability exists inindustrialization, population density, urbanizationand resource-use levels, creating pockets of high airpollution that are becoming critical environmentalconcerns. Transport sector is a major contributor tourban air pollution. Coal-based thermal powerplants; steel and cement plants have been majorcontributors to CO2, SO2 and particulate emissions.

.

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ARTICLE IN PRESSA. Garg et al. / Atmospheric Environment 40 (2006) 4608–4620 4609

CO and particulate emissions are the main sourcesof indoor air pollution. Emissions of the fluorinatedgases are also on the rise.

Many researchers have estimated Indian emissioninventories of different gases and years (Mitra,1991; ALGAS, 1998; Garg et al., 2001a,b; Reddyand Venkataraman, 2002; Garg and Shukla, 2002;Mitra and Bhattacharya, 2002; Garg et al., 2002;Mondal et al., 2004; PCRM, 2002). India hassubmitted the Initial National Communication(INC) to UNFCCC in June 2004 including inven-tory of CO2, methane and N2O using manydomestic emission factors (INC, 2004). The report-ing year is 1994 and this inventory is used as abenchmark for greenhouse gases (GHGs) for thecurrent study. The present paper is an attempt toincorporate the most recent scientific estimates forIndian emissions for consistent reporting of 10-gasemissions for 1985–2005 following the IPCC meth-odology. The GHGs covered are the six Kyotogases, namely carbon dioxide (CO2), methane(CH4), nitrous oxide (N2O), perfluorocarbons(PFCs), hydrofluorocarbons (HFCs) and sulfurhexafluoride (SF6). The local air pollutants coveredare sulfur dioxide (SO2), nitrogen oxides (NOX),carbon monoxide (CO) and total suspended parti-culates (TSP).

2. Methodology, activity data and emission factors

Emissions of each gas are attributed to specificsource categories. For example, source categoriesfor CO2 emissions are combustion of various fossilfuels (such as coal, petroleum oil products, naturalgas), and industrial processes (such as cement, ironand steel, lime and ammonia production). Similarlyimportant source categories for methane productionare enteric fermentation, rice paddy cultivation, coalmining, and municipal solid waste decomposition.According to IPCC methodology (IPCC, 1996),activity data for each source category is multipliedby respective emission factor to obtain emissionsfrom that source category for a specific gas. Tocalculate the total emissions of a gas from all itssource categories, the emissions are summed over allsource categories. We have used the followingequation for all gases unless specified otherwise:

EmissionsGas ¼X

source_cat

Activity datasource_cat

� Emission factorGas; source_cat

where EmissionsGas is the emissions of a given gasfrom all its source categories, Activity datasource_catis the amount of individual source category utilizedthat generates emissions of the gas under considera-tion, Emission factorGas; source_cat is the emissionfactor of a given gas by type of source category(emissions per unit of activity data utilized).

We have used actual activity data (to the extentavailable) for various source categories for allgases for 1985–2005. These have been primarilyderived from the published documents of theGovernment of India and state governments,reputed data organizations in India such as Centrefor Monitoring Indian Economy (CMIE), industrialassociations such as Cement Manufacturers’Association (CMA), international databases suchas International Energy Agency (IEA) and Enerda-ta, and some of our own surveys such as forbrick industry and captive power plants. Eachmajor activity data, e.g. sectoral coal and oilproduct consumption, have been verified fromalternate sources. The data used in the currentpaper have also been synchronized with INCsince the authors have had the privilege ofcoordinating the energy sector emissions inventoryfor INC. Moreover, we have also collected extensivelarge point sources and district level activitydata for India for 1990, 1995 and 2000 (Garget al., 2001a,b; Garg and Shukla, 2002; Kapsheet al., 2003). These provide rich depth and robust-ness to our sectoral activity data estimates. Someother independent inventory estimates for India(as cited earlier) either are for previous years or havenot taken INC information into consideration.These estimates also lack completeness, or usedefault emission factors, or use incomprehensivesources for activity data.

Official livestock census data for 1992, 1997 and2002 have been linearly extrapolated to derivelivestock populations for 1985–2005. Rice paddy,other crop production (also used to estimateagriculture crop residue for biomass combustion),and nitrogen fertilizer application data have beentaken from Fertilizer Association of India (FAI)and CMIE published statistics. Biomass combustiondata (fuel-wood and dry dung-cakes) have consider-able uncertainty. We have used the state levelconsumption averages from Rural Energy Databasefor fuel-wood and dung-cakes for 1990 afterconsulting prominent Indian experts. Livestockcensus data and average per head dung produc-tion/collection and use for fuel purposes are used to

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Table 1

Energy consumption during 1985–2005 in India

Fuel type Units 1985 1990 1995 2000 2005

Bituminous coal Tg 116.7 165.8 231.2 289 347

Lignite Tg 8.1 13.8 21.8 22.7 31

Coking coal Tg 36.5 47.7 51.9 51.6 56.2

Natural gas BCMa 4.2 10.9 19.1 23.3 31

Oil products Tg 43.3 58.6 78.8 108.8 132

Motor gasoline Tg 2.3 3.5 4.7 6.6 9

Diesel Tg 15.9 23.6 34.9 42.0 43

Kerosene Tg 6.2 8.4 9.9 11.3 12.6

Heavy fuel oil Tg 9.6 10.8 12.9 16.2 18.6

Sources: Synthesized and compiled from CMIE (2000, 2005),

OCC (1998), INC (2004) Enerdata database; IEA (2003).aBCM (Billion Cubic Meter)

1The NCV for coking coal has been measured as 24.18TJ/kt

(Choudhury et al., 2004) as against IPCC default value of

19.98TJ/kt, which was used in our previous estimates. However,

the measured carbon emission factors (93.6 t CO2/TJ) and IPCC

default (94.6 t CO2/TJ) are not much different. We have

estimated the emissions based on energy contents of fuels

combusted—i.e. activity data in TJ multiplied by emission factors

in ton CO2/TJ. Therefore, this increase in NCV increases the CO2

emissions by almost equivalent percentage.

A. Garg et al. / Atmospheric Environment 40 (2006) 4608–46204610

estimate dry-dung cakes consumption over1985–2005. Our earlier publications provide adetailed listing of activity data used and theirsources.

Table 1 provides aggregated energy consumptionfor main fuels for India during 1985–2005. Thisforms the basis of energy sector emission estimates.The data for 2005 were not available and we haveused the latest available year data (mostly 2004) andprojected it linearly to estimate 2005 activity data.Also some sectoral disaggregated data were notavailable, and we have used extrapolation fromknown years to estimate these. The fluorinated gasactivity data have been derived from detailed plantlevel bottom-up data and/or national importstatistics. These have been cited appropriately inthe respective sub-sections.

IPCC provides default emission factors forvarious source categories (IPCC, 1996). However,country-specific emission factors provide a moreaccurate estimation and we have tried to use India-specific emission factors to a large extent. Theseinclude CO2 emission factors from coal productcombustion; CO2 and NOX released from diesel andpetrol used in road transport; methane from coalmining; CO2 from cement, lime and nitric acidproduction processes; CH4 from enteric fermenta-tion and rice paddy cultivation; N2O from applica-tion of nitrogenous fertilizers and from soilssupporting rice—wheat systems; CO2, CH4, N2O,NOX and CO from burning of crop residue; andCH4 released from municipal solid waste. Theseemission factors are available in Mitra et al. (2004)and INC (2004).

3. The Official Indian Emissions Inventory

In 1994, 817Tg-CO2, 18.08 Tg-CH4, and 178Gg-N2O were emitted from India due to variousanthropogenic activities (INC, 2004). Thisamounted to 1252Tg-CO2 equivalent emissions.CO2 emissions contributed 65% of total GHGs,CH4 contributed 31% and 4% emissions werecontributed by N2O. On a sectoral basis, 61%CO2 equivalent of net GHGs were emitted from theenergy sector, 28% from the agriculture, 8% fromthe industrial processes, 2% from waste disposalactivities and the remaining 1% from land use, land-use change and forestry. Table 2 summarizes theGHG emissions from various sectors by sources andremovals by sinks for India for the year 1994.

4. Emission trends

4.1. Carbon dioxide

The 1994 official Indian CO2 emissions of 817Tg-CO2 are estimated to have grown to 1229Tg-CO2 in2005, growing around 4% per annum (Table 3).Removals from land use and land-use changeactivities are not considered. Based on the 1994inventory, CO2 emissions for 1995 have now beenrevised upwards by 9% from our previous estimatesfor the same year (Garg et al., 2001a). The mainchanges are the following;

�
The use of latest domestic emission factors forIndia (Mitra et al., 2004) explains about 1.4% ofthe upward revision. For example, the emissionestimates from coking coal combustion haveincreased by about 20% due to upward revisionof its net calorific value (NCV)1 (Choudhuryet al., 2004). Similarly the weighted average CO2
emission factors for clinker production inIndia have been estimated to be 0.537 t CO2/tclinker produced for 1994–1995 (and 0.53 for2001–2002), which is higher by 6–7.5% than theIPCC default values (Rao et al., 2004).

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Table 2

India’s initial national greenhouse gas inventories (in Giga Gram) of anthropogenic emissions by sources and removals by sinks of all

greenhouse gases not controlled by the Montreal Protocol for the base year 1994

Greenhouse gas source and sink categories CO2 (emissions) CO2 (removals) CH4 N2O CO2 equivalent

emissionsa

Total (Net) National Emission (Giga gram

per year)

817 023 23 533 18 083 178 1 228 540

1. All energy

Fuel combustion 679 470 2896 11.4 743 810

Energy and transformation industries 353 518 4.9 355 037

Industry 149 806 2.8 150 674

Transport 79 880 9 0.7 80 286

Commercial-institutional 20 509 0.2 20 571

Residential 43 794 0.4 43 918

All other sectors 31 963 0.4 32 087

Biomass burnt for energy 1636 2.0 34 976

Fugitive fuel emission

Oil and natural gas system 601 12 621

Coal mining 650 13 650

2. Industrial processes 99 878 2 9 102 710

3. Agriculture 14 175 151 344 485

Enteric fermentation 8972 188 412

Manure management 946 1 20 176

Rice cultivation 4090 85 890

Agricultural crop residue 167 4 4747

Emission from soils 146 45 260

4. Land use, land-use change and forestry 37 675 23 533 6.5 0.04 14 292

Changes in forest and other woody biomass

stock

14 252 (14 252)

Forest and grassland conversion 17 987 17 987

Trace gases from biomass burning 6.5 0.04 150

Uptake from abandonment of managed

lands

9281 (9281)

Emissions and removals from soils 19 688 19 688

5. Other sources as appropriate and to the

extent possible

5a. Waste 1003 7 23 233

Municipal solid waste disposal 582 12 222

Domestic waste water 359 7539

Industrial waste water 62 1302

Human sewage 7 2170

5b. Emissions from bunker fuelsb 3373 3373

Aviation 2880 2880

Navigation 493 493

Source: India’s Initial National Communication to the UNFCCC, 2004.aConverted by using Global warming potential (GWP) indexed multipliers of 21 and 310 for converting CH4 and N2O, respectively.bNot counted in the national totals.

A. Garg et al. / Atmospheric Environment 40 (2006) 4608–4620 4611

�
Coal imports of 13.1Mt (including 9.5Mt cokingcoal) have now been added to the national coalproducts combustion activity data. This explainsabout 3.6% upward revision in national CO2
emissions.
� Reporting industrial process emissions from a
few sources that were not captured in the earlierestimates. These sources add about 26Tg-CO2 tothe ‘‘Other industries’’ category, explaining 3.3%

of the upward revision. These include CO2

emissions from lime production, limestone anddolomite use, ammonia production, carbideproduction, ferro alloy production and alumi-num production.
� Improvement in activity data for some cate-
gories, such as ‘‘other sectors’’ and ‘‘Otherindustries’’ captures the remaining 0.7% upwardrevision.

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Table 3

Sectoral CO2 emissions in Tg-CO2

Sector 1985 1990 1995 2000 2005 CAGR % (1985–2005)

Power 146 231 392 517 638 7.7

Road 47 70 89 116 143 5.7

Railway 20 14 6 5 6 �5.8

Aviation 2 2.5 3 4 5 4.7

Shipping 0.4 0.5 0.6 0.8 1 4.7

Cement 28 43 62 77 98 6.5

Iron and steel 56 74 86 92 103 3.1

Fertilizer 20 22 23 23 24 1.0

Other industries 62 82 93 100 109 2.9

Other sectors 59 76 94 97 102 2.8

All India 440 615 849 1032 1229 5.3

Note: CAGR (compounded annual growth rate).


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2

pow

is t

There is also some re-allocation of emissionsbetween the categories ‘‘other industries’’ and‘‘other sectors’’. This does not result in anychange in overall national emission estimates.

Coal use contributes two-thirds of total nationalCO2 emissions. These are mainly from power, steeland cement sectors. India consumed 161Tg coalproducts in 1985 and about 434Tg in 2005, withpower sector accounting for 50% and 72% of thisconsumption, respectively. Transport sector formsthe bulk of CO2 emissions from oil productcombustion, The share of electric power generationin India’s CO2 emissions has increased from 33% to52% during 1985–2005 and majority of it comesfrom coal and lignite consumption (Table 3).Cement sector has also grown, especially sincemid-nineties spurred by national thrust on infra-structure and highways development. Railwaytransport sector has witnessed a negative growthin its CO2 emissions due to phasing out of coal-powered steam traction throughout India andenhanced electric traction on high-density corridors.Other industries, which include textiles, chemicals,metals, brick, paper, sugar, engineering, etc. havewitnessed a milder growth in CO2 emissionswith the government policy to promote energyefficiency measures in small and medium scaleindustries, and enhanced electricity penetrationsince mid-nineties.2 Similar is the case with ‘‘other

Electric power sector emissions are accounted for separately at

er generation point and not at each consumption point. This

o avoid double counting of emissions.

sectors,’’ which includes services, commercial andresidential sectors.

4.2. Methane

Agriculture sector contributed 83% of all Indiamethane emissions in 2005 including 53% fromlivestock-related activities, 20% from rice paddycultivation and 10% from biomass burning (Table 4).The largest contributing factors for CH4 emissionsin India are low digestibility of animal feed (entericfermentation) and rice paddy cultivation undercontinuous submergence. Both these are widely dis-persed activities. Although specific mitigation mea-sures like strategic supplementation of feed throughmolasses urea, multi-nutrient blocks and low bypassprotein have been suggested for improving lowdigestibility of animal feed (ALGAS, 1998), theirimplementation may pose a formidable challenge.Development of less methane-intensive paddy vari-eties may be a relatively easier option.

Methane emissions from disposal and treatmentof industrial and municipal waste are not aprominent source in India, except in large urbancenters. Fugitive methane emissions from fossil fuelsare relatively localized with only a dozen districtscontributing more than 90% of all India coal andlignite production, and even lesser for oil andnatural gas production.

4.3. Nitrous oxide

This study estimates direct N2O emissionsfrom soils (including use of synthetic fertilizers),field burning of agriculture crop residue, manure

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Table 4

CH4 emissions from various source categories in Tg-CH4

Source categories 1985 1990 1995 2000 2005 CAGR % (1985–2005)

Enteric fermentation 8.80 9.00 9.42 9.60 9.62 0.4

Paddy cultivation 4.01 4.02 4.08 4.03 4.02 0.0

Biomass burnt for energy 1.61 1.62 1.67 1.76 1.80 0.6

MSW disposal 0.62 0.68 0.75 0.84 0.96 2.2

Manure management 0.90 0.95 0.99 1.01 1.00 0.5

Oil and natural gas related 0.23 0.50 0.64 0.91 1.04 7.9

Waste water disposal 0.36 0.39 0.45 0.56 0.67 3.2

Coal production 0.51 0.57 0.67 0.72 0.79 2.2

Agriculture crop residue burning 0.17 0.18 0.181 0.183 0.182 0.3

Total CH4 17.21 17.92 18.85 19.61 20.08 0.8

Table 5

N2O emissions from various source categories in Gg-N2O


Synthetic fertilizer use 80 94 109 129 151 3.2

Field burning of agriculture residue 15 18 21 21 20 1.4

Indirect soil emissions 17 19 21 25 30 2.9

Manure management 4 5 6 6 8 3.9

Fossil fuel combustion 7 9 12 15 19 4.9

Industrial processes 6 7 9 12 16 5.0

Waste 5 6 7 8 9 2.8

Total N2O 134 158 185 217 253 3.2


management, indirect soil emissions, fossil fuelcombustion, industrial activities namely productionof nitric acid, and waste sector (Table 5). IPCCmethodologies have been followed for theseestimations (IPCC, 1996; Garg and Shukla,2002). India reported 178Gg-N2O emissions for1994. This has been taken to benchmark thepresent emission estimates. There has been anappreciable lowering in direct N2O emission esti-mates from soils, including from use of syntheticfertilizers. This is mainly due to the use of India-specific emission factors that are lower by almost30% than the IPCC default values. These arehowever in the suggested uncertainty ranges ofIPCC default emission factors. The previous emis-sion factors were 0.93 kg ha�1N2O–N for all typesof crop regimes. The revised emission factors usedfor rice–wheat systems are 0.76 for rice and0.66 kg ha�1N2O–N for wheat for urea applicationwithout any inhibitors (Pathak et al., 2004).Application of inhibitors reduces N2O productionrates by up to 15% and is considered for the revisednational emissions.

Agriculture sector activities account for morethan 80% of the total N2O emission including 60%from use of synthetic fertilizer, about 12% eachfrom agriculture residue burning and indirect soilemissions and about 3% from manure management.This has remained more or less the same throughout1985–2005. Emissions from agriculture sector arewidely dispersed and will require substantial mitiga-tion efforts.

4.4. Perfluorocarbons (PFCs)

PFCs are fully fluorinated hydrocarbons withvery high global warming potential due to theirextremely long atmospheric lifetimes (2600–50,000years). The major sources of PFC emissions in Indiaare aluminum production and semiconductor man-ufacturing. Aluminum is produced by five largecompanies in India and their annual productiondata have been used for estimating national PFCemissions, multiplying by a weighted averageIPCC default emission factor of 1.4 kg of CF4/t ofaluminum produced (IPCC, 1996). Further, the

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Table 7

HFC emissions in Gg-CO2 equivalents

Emissions GWP 1990 1995 2000 2005 CAGR (%)

HFC-134a 1300 – – 285 1437 38

HFC-152a 190 – 1 2 6 23

HFC-227ea 3800 – 61 137 271 16

HFC-23 11700 873 2004 4936 9500 17

Total HFCs 873 2066 5361 11214 19

Table 6

PFC emissions from various source categories in Gg-CO2 equivalents

Emissions GWP 1985 1990 1995 2000 2005 CAGR % (1985–2005)

CF4 6500 2425 4040 4435 5637 6867 5.3

C2F6 9200 343 572 628 798 972 5.3

Imports – 263 438 540 687 930 6.5

Total PFCs 3031 5049 5603 7121 8769 5.5


emission factor for C2F6 is taken as 10 times lowerthan that of CF4 (Devotta and Asthana, 2004).

Apart from CF4 and C2F6 emissions due toprimary aluminum production, PFCs are alsoimported for use in electronic industry for makingsemiconductors. In absence of any reliable informa-tion on the level and extent of imports, it has beenassumed that imports contribute about 8–10% PFCemissions annually (Devotta and Asthana, 2004).Table 6 presents the total PFC emission trends. Thecompounded annual growth rate (CAGR) is samefor CF4 and C2F6 since their emissions are directlyrelated to aluminum production.

4.5. Hydrofluorocarbons (HFCs)

HFCs are gaseous compounds that are replacingozone-depleting CFCs as refrigerant. Indian HFCemissions have been estimated by multiplying theirannual national consumption with their respectiveglobal warming potential in CO2 equivalent terms(Devotta and Asthana, 2004), as per IPCC tier 1methodology (IPCC, 1996). Currently, the mostwidely used HFC in India is HFC-134a, which is thepopular choice for domestic and commercial refrig-eration including automobiles. Use of HFC-134astarted around 1994–1995 and has grown appreci-ably as air conditioner market has grown over 20%annually since mid-1990s.

Another compound, HFC-152a is used to a verylimited extent in glass industries. HFC-227ea is usedin Metered Dose Inhalers and as a fire-extinguishingagent in fire extinguishers. Another important HFC,HFC-23 is generated as a by-product at the rate of2–4% of HCFC-22 production (IPCC, 1996). HFC-23 has a very high global warming potential.

Table 7 presents total estimated HFC emissionsin Gg-CO2 equivalent for HFC-134a, HFC-23,HFC-227ea and HFC-152a. The major contributiontowards HFC emission is due to HFC-23, which hasgrown at a fast rate from a low base. However, it

also offers focused mitigation opportunities throughits thermal oxidation.

4.6. Sulfur hexafluoride

Sulfur hexafluoride is an extremely stable atmo-spheric trace gas and has an estimated atmosphericlifetime of 3200 years and a GWP of 23,900. Itsunique physio-chemical properties make this gasideally suited for many specialized industrial appli-cations such as in transformers and circuit breakers.Most of its emissions in India originate from its usefor insulation of high-voltage equipment. Only aminiscule are emitted from magnesium foundries(cast), where SF6 is used to prevent oxidation ofmolten magnesium.

There is considerable difficulty in acquiring SF6

consumption data for India. Currently, the entireIndian requirement of SF6 is imported. SF6 emis-sions have been estimated by multiplying theirannual consumption (equal to total imports) withtheir global warming potential as per IPCC tier 1methodology (IPCC, 1996). Our estimates indicatetotal SF6 emissions at 87Gg-CO2 equivalent in 2000and 2084Gg-CO2 equivalent in 2005.

4.7. Sulfur dioxide

SO2 emissions due to fossil fuel combustion aredirectly related to the sulfur contents of the fuel.

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Table 8

Sectoral SO2 emissions in Tg-SO2

Source/sector 1985 1990 1995 2000 2005 CAGR (1985–2005)

Power 0.723 1.047 1.745 2.300 2.720 6.8

Steel 0.210 0.262 0.280 0.310 0.347 2.5

Fertilizer 0.125 0.106 0.125 0.124 0.130 0.2

Cement 0.074 0.097 0.108 0.160 0.206 5.2

Other industries 0.438 0.576 0.605 0.651 0.724 2.5

Road 0.255 0.201 0.243 0.138 0.085 �5.3

Rail 0.130 0.069 0.027 0.011 0.012 �11.2

Shipping 0.006 0.008 0.010 0.013 0.015 4.6

Aviation 0.008 0.009 0.006 0.007 0.009 0.8

Biomass burning 0.215 0.216 0.217 0.215 0.210 �0.1

Sulfuric acid 0.040 0.045 0.053 0.061 0.066 2.5

Lead smelting 0.006 0.008 0.011 0.013 0.015 4.6

Zinc smelting 0.015 0.016 0.014 0.015 0.016 0.3

Copper smelting 0.016 0.027 0.041 0.050 0.052 6.1

Other sectors 0.130 0.160 0.178 0.190 0.192 2.0

All India 2.39 2.85 3.66 4.26 4.80 3.5


During coal combustion, sulfur is not releasedcompletely and is partly retained in ash. The sulfurretention in ash for coal may range from 5% to 60%of original sulfur contents (IPCC, 1996) and is takenas 10% for India (Choudhury et al., 2004). Biomassburning is the other energy source of SO2 emissions.Some non-energy sources also contribute to SO2

emissions like sulfuric acid production and smeltingof zinc, copper and lead ores.

The Indian SO2 emissions have grown from2.39Tg in 1985 to 4.8 Tg in 2005 (Table 8). Somerecent policy decisions of the Government of Indiawould contribute reducing SO2 emissions in future.These include a new automobile fuel policy forIndia, sulfur content reduction in petroleum oilproducts, Euro 2 compliant road vehicles from2005, and mandatory washing of coal that is used700 km away from the mine mouth (Mashelkaret al., 2002). The latter measure is aimed at reducingfly ash and also simultaneously reduces sulfur by15–20%. Since over a third of coal is used beyond700 km, this measure is expected to start reducingSO2 from coal use in near future.

The reduction in road emissions represents aninteresting dynamics evolving in India. Gasolineand diesel are the major auto-fuels used in India.Generally, personal transport like two-wheelers runon gasoline and the public/commercial transportlike three-wheelers, taxis, light and heavy-dutyvehicles run on diesel. A directive of the SupremeCourt of India has resulted in conversion of morethan 40,000 diesel vehicles (including buses, taxis

and three-wheelers) to CNG in the national capitalDelhi by 31 January 2003. This forced fuel switchinghas resulted in considerable reduction in particulateand SO2 emissions in Delhi. Such initiatives are alsounderway in some other major cities.

Majority of personal cars still run on diesel sinceit is cheaper than gasoline. However, the sulfurcontent in the diesel oil supplied to the entirecountry has been decreased from 1% sulfur byweight to 0.25% (during 2000) and for the fourlargest cities to 0.05% (late 2001) by the Indianrefineries as per the Indian government directives.The maximum sulfur content in gasoline has alsobeen reduced from 0.2% to 0.1% in the entirecountry (during 2000) and to 0.05% in the fourlargest cities (during 2001). These have resulted inan appreciable decrease in SO2 emissions from thetransport sector.

Policy dynamics to mitigate local pollution isprojected to manifest in a reduction in SO2

emissions in future even though the absolute energyconsumption, and therefore CO2 emissions, wouldcontinue to rise (Garg et al., 2003; Kapshe et al.,2003).

4.8. Nitrogen oxides

Nitrogen oxides are indirect GHGs. They havebeen the targets of environmental policies for theirrole in forming ozone (O3), as well for their directacidification effects. The NOX emissions frommobile sources are related to the air–fuel mix and

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Table 9

NOX emissions from different sectors in Tg-NOX


Power 0.377 0.620 0.964 1.283 1.547 7.3

Road 0.520 0.670 0.985 1.380 1.696 6.1

Rail 0.120 0.101 0.100 0.110 0.132 0.5

Navigation 0.010 0.012 0.014 0.018 0.023 4.3

Aviation 0.018 0.024 0.033 0.042 0.051 5.4

Cement 0.040 0.060 0.085 0.116 0.148 6.7

Steel 0.123 0.152 0.181 0.206 0.231 3.2

Brick 0.078 0.094 0.109 0.133 0.165 3.8


Biomass burning 0.586 0.633 0.670 0.670 0.650 0.5

Nitric acid production 0.002 0.004 0.006 0.011 0.013 9.8

Other sectors 0.030 0.040 0.046 0.049 0.051 2.7

All India (Tg-NOX) 2.11 2.64 3.46 4.31 5.02 4.4

Table 10

CO emissions from different sectors in Tg-CO

Sectors 1985 1990 1995 2000 2005 CAGR % (1985–2005)

Residential 31.3 32.1 33.3 34.8 35.9 0.7

Transport 1.99 2.5 3.22 4.47 5.35 5.1

Power 0.10 0.15 0.30 0.35 0.45 7.6

Brick 0.21 0.30 0.42 0.57 0.78 6.7


All India 33.7 35.1 37.2 40.3 41.7 1.1


combustion temperatures, as well as the installedpollution control equipment in the vehicle. Dieselvehicles emit more NOX as compared to petrol-driven vehicles. NOX emission from heavy-dutyvehicles is significantly higher than those for carsand light commercial vehicles. Other than thesefossil fuel combustion source categories for NOX

emissions, nitric acid production is the main non-energy source of NOX emissions. Nitric acid isproduced from the catalytic oxidation of ammoniaand nitrogen oxides are released in the process.Emissions are estimated from the amount of nitricacid produced.

India emitted around 5.12Tg NOX in 2005 as perour estimates growing at about 4.5% per annumbetween 1985–2005 (Table 9). Coal and oil combus-tion have almost equal shares in total NOX

emissions. Coal combustion is mainly in powergeneration sector. The oil product emissions aremostly from diesel combustion in transport sectorthat has more than doubled during 1985–2000.Road transport sector is the predominant source ofNOX emissions contributing 34% to Indian emis-

sions in 2005. Power generation is the next largestcontributor at 30% while industry about 17%. Theremaining emissions are accounted for by biomassconsumption and nitric acid production. Analysis ofchanging sectoral NOX emission shares during1985–2005 indicates an increase in power sectorshare from 18% to 30% and road transport from25% to 33%. On the contrary, the emission share ofbiomass burning has declined from 28% to 15%,other industries (10–6%) and railways (6–3%). Itmust be noted here that absolute emissions from allthese sources have increased during this period.Differential growth rates result in changing emis-sion shares.

4.9. Carbon mono-oxide

Carbon mono-oxide emissions are mostly due toinefficient and incomplete burning. Biomass burn-ing (fuel-wood, dung-cakes and agriculture cropresidue), especially for cooking in the rural house-holds is the main source, followed by road transport(Table 10). Biomass burning produces considerable

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Table 11

TSP emissions from different sectors in Tg-TSP

Sources 1985 1990 1995 2000 2005 CAGR % (1985–2005)

Residential 3.94 4.13 4.19 4.23 4.18 0.3

Power 2.60 2.91 3.26 1.57 0.79 �5.8

Transport 0.93 1.38 1.69 2.04 2.19 4.4

Cement 0.23 0.30 0.40 0.51 0.54 4.5

Brick 0.36 0.41 0.50 0.66 0.88 4.6


Other sectors 0.05 0.06 0.07 0.08 0.09 3.0

All India 8.12 9.21 10.13 9.13 8.72 0.4


CO most of which is indoors and is one of thesources of adverse health impacts on womenand children (particulate emissions are the mainsource). The emission factors used are: coalcombustion (90 t-CO/PJ of fuel combusted), oil(65) and biomass (1000). It must be noted herethat the uncertainty in these factors and activitydata for biomass burnt is high. The emissiongrowth rate from these activities is low. Asenergy efficient technologies and cleaner fuelspenetrate in rural areas, these emissions shouldreduce considerably.

4.10. Particulates

Estimation of TSP emissions is severely con-strained by the uncertainty around activity data,especially biomass combustion—the predominantsource. The range in emission factors could have avariability of 300%, adding appreciably to emissionuncertainty (Parashar et al., 2005; Reddy andVenkataraman, 2002). Secondary particulate emis-sions are not estimated in the current study.Residential sector is the largest emitter of TSP withabout 4.2 Tg emissions in 2005, due to biomasscombustion for cooking and kerosene for lighting(Table 11). There is a declining trend in nationalTSP emissions after mid-nineties, mainly contrib-uted by stricter enforcement of emission standardsin organized sector. Although power sector iswitnessing considerable growth, the particulateemissions are slowly decreasing due to strictermonitoring and control of end-of-the-pipe technol-ogies installed, such as electro static precipitators(ESPs).

The emissions from transport sector are mostlyfrom diesel combustion in road transport. Althoughrailway and water-borne transport emits consider-able TSP emissions per unit of fuel consumed, the

size of their total activities are small as compared toroad transport. TSP emissions from road transporthave increased due to a dominant share of diesel infreight and increase in the percentage of diesel-driven passenger vehicles. However, the recentintroduction of Euro-II equivalent norms andcleaning of diesel is resulting in a lower rate ofgrowth of TSP emission from road transport ascompared to the absolute growth of road traffic.

The cement industry emission dynamics has twodimensions. The first is the gradual phasing out ofwet cement plants by dry plants resulting inincreased emissions since mid-nineties. The secondis tightening of emission standards and bettermonitoring of bag filters, centrifugal filters andESPs at cement plants. The emission norms are verystringent and stricter enforcement is slowly resultingin a reduction in particulate emissions from thecement industry.

Brick industry TSP emissions are growing veryfast with a spurt in brick demand nationally andprevalent use of predominantly rudimentary tech-nology and process controls. Brick kilns in Indiaconsume considerable biomass, low-grade coal, andused fuel oil.

There has been considerable change in the shareof different sectors in TSP emissions over1985–2005. Power sector share has declined from32% in 1985 to 9% in 2005 mainly due to stricterenforcement of existing emission standards. Trans-port sector share has increased from 11% to 25%during 1985–2005 due to higher activity levels. Theunorganized sectors such as residential and brickcontinue to have high TSP emissions. Indoor airpollution in rural and semi-urban households thathave profound human health impacts are alsocaused by these emissions. Therefore, technologicalimprovements and interventions for a low carboneconomy in rural areas would have to include

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Table 12

Multigas emission trends for India over 1985–2005 in Tg

Emissions 1985 1990 1995 2000 2005 CAGR % (1985–2005)

CO2 440 615 849 1032 1229 5.3

CH4 17.21 17.92 18.85 19.61 20.08 0.8

N2O 0.134 0.158 0.185 0.217 0.253 3.2

PFC (CO2 Eq.) 3 5 6 7 9 5.5

HFC (CO2 Eq.) — 1 2 5 11 18.6

SF6 (CO2 Eq.) — — — 0.1 2 88.7

GHG (CO2 Eq.)a 846 1046 1310 1523 1751 3.7

SO2 2.39 2.85 3.66 4.26 4.80 3.5

NOX 2.11 2.64 3.46 4.31 5.02 4.4

CO 33.7 35.1 37.2 40.3 41.7 1.1

TSP 8.1 9.2 10.1 9.1 8.7 0.4

aIncludes CO2, CH4, N2O, PFC, HFC and SF6. Global warming potentials of 1, 21 and 310 are used for CO2, CH4 and N2O,

respectively.


technologies for cooking and lighting that effec-tively mitigate particulate and CO emissions.

5. Conclusions

The overall multigas emission trends for India aresummarized in Table 12. India emitted 846Tg-CO2

equivalent GHG emissions in 1985 that grew to1751Tg-CO2 equivalent in 2005. The multigasemissions show that the sector and fuel contribu-tions vary across gases, as well as regions. Coalconsumption in power sector dominates CO2 andSO2 emissions, while power and road transportequally contribute to NOX emissions. The agricul-ture sector contribute most to the CH4 emissionsarising from rice cultivation and livestock, whilesynthetic fertilizer use in agriculture is the over-whelming source of N2O emissions. Among PFCemissions, most are C2F6 and CF4 emissions fromaluminum production. The majority of HFC emis-sions are contributed by HFC-23, a by-productduring the production of HCFC-22 that is widelyused in refrigeration industry. Most CO emissionsarise from biomass burning. Particulate emissionsmostly arise from biomass burning in residentialsector, fossil fuel use in road transport and coalcombustion in large industrial plants. These variedemission patterns provide interesting policy linksand disjoints, such as which and where mitigationflexibility for the Kyoto gases, exploring co-benefitsof CO2 and SO2 mitigation, and technology anddevelopment pathway dependence of emissions.

The analysis shows that while emissions fromIndia are growing, their growth rates are decliningsince 2000 for all the gases except for the F-gases

due to their use as replacement for ozone-depletingsubstances. The contributing factors to thesedeclining growth rates for CO2 emission includeimproving performance of coal-based power plants,policies pushing more energy efficient automobiles,targeted energy efficiency measures by large produ-cers of energy-intensive commodities like the SteelAuthority of India that produces nearly two-thirdsof Indian steel, and changeover to dry cementproduction process by increasingly consolidatingIndian cement industry. N2O emission growth rateis declining marginally as synthetic fertilizer use isbecoming more efficient. In agriculture, agricultureextension services promoted by the Government foreducating and helping farmers for more efficientand effective utilization of input resources havecontributed to reducing emissions of methane andN2O per unit of production. In the aggregate, theprofile of GHG emissions have become more CO2

dominant over the 20 year period from 1985 to2005, while the share of methane emissions havecontinued to decline (Fig. 1). The contribution ofCO2 to India’s GHG emissions over the period hasincreased from 52% in 1985 to 71% in 2005. Therapid growth in energy demand and continuedreliance on fossil fuels are the drivers of high growthof CO2 emissions, whereas methane emissionhave grown at lower rate as these are driven byagriculture sector which has grown at a relativelylower pace during the same period.

The policies mandating successive reduction insulfur content of petroleum products has been a keycontributor to reduced SO2 emissions over past fiveyears, while the relative reduction in TSP emission ismainly due to enforcement of the use of ESP in

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1985

CH443%

F-gases0.4% N2O

5%

CO252%

2005CO271%

N2O4%

F-gases1% CH4

24%

Fig. 1. Greenhouse gas emission trends over 1985–2005 in CO2-equivalent terms.


power plants and industries using coal, andefficiency measures in industries. The growth ratesof NOX emission has retarded due to improvedtechnologies in power sector and introduction ofEuro-II norms for automobiles. The reduction ingrowth rate of carbon monoxide emission is moregradual since cleaner technology and fuels arepenetrating relatively slowly in rural cooking wherea vast population still continues to use inefficientbiomass stoves with below 10% combustion effi-ciency. This is a vital area for technology strategyfor three reasons: (a) the energy use via thesetechnologies represent nearly a quarter of totalenergy use in India; (b) the indoor air pollution(mainly particulate and carbon mono-oxide) causedby these technologies is a major cause of healthdamage among the low income population; (c) frommarket perspective these technologies offer a sizable‘‘no regret’’ potential. The technology policiesduring past two decades to harness these ‘‘lowhanging fruits’’ have met with myriad barriers butshould however be pursued with fresh institutionalinitiatives.

Another important insight is the differentialgrowth rates for GHG and local air pollutantemissions. The former, especially the dominant CO2

emissions, are growing faster than the latter. Thedriving forces of emission growths are also in-herently different. While formal public initiativesare being increasingly instituted to mitigate localpollution, the GHG emission intensity is improvedmainly due to enhanced competition in the wake ofeconomic reforms such as energy efficiency mea-sures by companies. The expectations of higheractivity levels in the coming years, namely morepower generation, increased industrial outputsand more private transport, imply that GHGemissions would continue to rise in absolute terms,though the emissions intensity of the economywould continue to improve. The present inventory

assessment is a pointer to the future emissionpathways for India wherein local air pollutant andGHG emissions, although connected, may not movein synchronization and therefore would requirealignment through well crafted development andenvironment strategies.

Acknowledgments

The authors have benefited from discussions withDr. A.P. Mitra, Dr. Subodh Sharma and otherinventory experts involved in India’s Initial Na-tional Communication preparation process. We alsoacknowledge Dr. M. Kainuma, Prof. Y. Matsuoka,Mr. Go Hibino and other experts for their reviewcomments on the draft paper presentation at theAIM Workshop during February 2006.

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The sectoral trends of multigas emissions inventory of India