| HOME > Articles and Reports > Major Findings 7
Study on Kolkata, Delhi and Manila (1) Introduction The urbanization is a part and parcel of the human development process and, therefore, has witnessed a sharp increase in the last few decades of industrial era. In 1900, only 160 million people (one tenth of the then population) were living in the urban areas but by 2006, almost 3.2 billion people are expected to inhabit the urban areas1. This will be about half of the total world's population. Most of this projected growth will occur in the developing countries due to reasons like aspiration for economic prosperity, better social and civic amenities, degradation of rural areas and population increase. The industrialization has totally changed the human settlement pattern. During the period up to about 1950, most of the jobs were in the agriculture fields only, confining the population to rural areas, but now most of the jobs are in service sector which is an out growth of industrialization1 propelling the people towards urban centers. Cities take up only about 2% of the world's available surface area but consume bulk of the key resources. It has been estimated that roughly 78% of carbon emissions from fossil fuel combustion and cement manufacturing, and 76% of industrial wood use occur in urban areas. Almost 60% of the total water tapped in the world for human consumption is consumed by the cities. Almost half of this water is used for irrigating the food crops consumed by city dwellers, roughly a third is used by city industries and the remainder is used to meet the requirement of sanitation and drinking water1. The cities represent a massive concentration of all human activities. But there has been a difference of opinion in regarding cities as eco-hazards or eco-devices. On one hand such a massive concentrations of human activities can be considered naturally unviable due to extraction of huge resources but on the other hand, can also provide an opportunity to use these as eco-devices offering an opportunity for better and sustainable management of natural and human resources in geographically smaller and manageable area. Considerable efforts are underway to understand the various effects of urbanization to resolve this issue. One such effort is APN/IGES sponsored Asian Mega-city Programme which has been underway since last two years. In India, under this program, study of two of India's mega-cities, namely Delhi and Kolkata and Manila city of Philippines have been under taken to find out environmental consequences of the developmental process in these mega-cities. A number of trace atmospheric gases from different sources in these cities have been estimated, which include both direct emissions sources (e.g. emissions of carbon dioxide from fossil fuel consumption, methane emission from waste sectors etc.) as well as indirect emissions sources (i.e. embodied emission e.g. methane emission from rice paddy fields catering the need of rice consumed by city population or methane emission from animals providing milk to city population). The significance of these emissions in the national context is also being examined. At present as per 2001 Indian census, there are more than thirty million plus cities in India with rapid developmental and industrial activities. Delhi and Kolkata (earlier known as Calcutta) are the two important mega-cities in India with different techno-socio-economic settings. The total population of the cities together was about 20 millions in 1990 but has increased to about 29 millions in 2000 as a result of rapid urbanization. The future population has been projected to be about 20 millions for Delhi and 25 millions for Kolkata in 2015. Table 4-4-7-1 shows some interesting indicators reflecting different socio-economic and cultural features of India's four mega-cities namely Kolkata, Delhi, Bangalore and Mumbai2 for the year 2001-2002. Delhi is the most affluent city in India having highest per-capita income, highest number of cars per thousand population, highest number of cell phones, highest number of expensive cars sold, and also highest amount of personal income tax collected. Kolkata, on the other hand, is almost at the bottom of this ladder among these mega-cities. Traditionally, Kolkata inhabitants are of different cultural habit than that of inhabitants of Delhi, which are more consuming society. But now in Kolkata too, change in trend is felt and it is also changing to a more consuming society. Due to these interesting differences, Delhi and Kolkata provides two different scenarios to study the environmental consequences of urbanization.  Metro Manila or the National Capital Region has a land area of 636 square kilometers, accounting for approximately 0.21 percent of the Philippines' total land area of 300,000 square kilometers. It is composed of four (4) districts with twelve (12) cities and five (5) municipalities. It is geographically located at 140 20' to 140 50' latitude and 1200 54' to 121010' longitude. Its climate is characterized by two pronounced seasons. It is normally dry from January to May, with April and May as the hottest months, and rainy during the rest of the year. Temperatures in Metro Manila measures as much as 31.2oC and as low as 24.8oC. In terms of tropical cyclone, the National Capital Region has been visited by a total of 39 tropical cyclones for the 1970 to 2000 period or approximately a frequency of 5 cyclones in 4 years. Despite being the smallest in terms of land area, Metro Manila has the biggest contribution to the country's Gross Domestic Product (GDP). At an average, it comprises 30 % of the Philippines' GDP. And with the premier airports and ports located in it, Metro Manila serves as the distribution center for exports and capital goods. It also provides almost half of the total national output in manufacturing, commerce and services.According to the latest census conducted on May 2000, Metro Manila has a population of almost 10 Million (9,932,560), making it a megacity by definition. NCR is also the most densely populated region with 15,617 persons occupying a square km of land, 61 times the national figure of 255 persons per square km. (2) Emissions of trace gases and particulate matter from direct and indirect (embodied) sources In order to study the impacts of developmental processes on the environment in the mega-cities, for the first time, an attempt has been made to calculate embodied emissions in the material and energy that flow in the mega-cities. Besides, emissions of both long lived greenhouse gases like carbon dioxide (CO2) and methane (CH4) as well as short-lived gases like carbon monoxide (CO), Oxides of nitrogen (NOx), black carbon (BC), organic carbon (OC) and particulate matter (PM) have also been estimated. These numbers, although still associated with large uncertainties due to involved complexities, nevertheless give some idea of the magnitude of emissions associated with the development and maintenance of mega-cities. Here we are presenting our work on emissions from energy sector. For the calculation of inventory values, in most of the cases IPCC-1996 methodologies3 have been followed. However, wherever country specific values of emission factors are available, the same has been utilized. Emissions from energy sector: Energy is the key driver of most of the world's economies, which is also primarily responsible for the emissions of greenhouse gases into the environment, considered to be responsible for the global warming. In India, more than 85% of the total CO2 emissions have been estimated to be coming out of the energy related activities like consumption of fossil and bio fuels in total CO2 emissions during 19904. Unlike the developed economies, traditional fuels like fuel-wood, crop residues, and animal waste etc. have significant contribution, which are estimated to account for about 40% of the total energy consumption in India4. The energy consumed in the metropolitan area consists of coal, petroleum, diesel and bio-fuel. The consumption of biomass fuel mainly in the form of wood and dung-cake has been found much more in Kolkata than in Delhi. There is also a noticeable change in the consumption pattern in Kolkata from 192-92 to 1997-98. The industrial consumption was less in 1997 - 98 compared to that in 1992 - 93 periods, perhaps due to a decline in the industrial activity in the area. On the contrary, the coal consumption increased significantly during this period mainly for generation of thermal power. Consumption of energy is always associated with the pollution of the environment with increased emissions of suspended particulates, carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxides, and other hydrocarbons. Both the suspended particulate matter as well as other form of pollutants in the metropolitan area is dominated by emissions from thermal power plants. Figure-1 shows the estimated carbon dioxide emissions from Delhi and Kolkata for different sources. This figure reveals that the major contributor of CO2 emission in both Delhi and Kolkata is electricity consumption (including both direct and embodied). The embodied CO2 emissions associated with steel and cement consumption also have significant contributions in the city totals. For the assessment of source strength of materials consumed in Delhi and Kolkata like coal, gasoline (petrol), diesel, fuel wood and dung cakes for the emissions of greenhouse gases, we have used IPCC 1996 top-down approach3 using the consumption figures. The bio-fuel consumption in Delhi has been reported to be negligible but in Kolkata, it is one of the important sources for meeting household energy requirements. The consumption of bio-fuels also emits methane, which has also been estimated as per IPCC-1996 guidelines for different years. The consumption of bio-fuels like fuel-wood and dung cakes in Kolkata has recorded an increase during the period 1990-91 to 1997-98 and consequently methane emission also shows an increasing trend of emission during this period. The results show that the contribution of methane emission from fuel-wood consumption is almost five times higher than the methane emission from dung-cake consumption in Kolkata. In Delhi, the direct emission of CO2 has been found to be highest from the consumption of diesel followed by gasoline. The coal consumption in the thermal power stations in Delhi has been reduced, as these are now being operated upon natural gas. More over most of the electricity supplied to Delhi city is being drawn from the national grid as local electricity production is very small. However, when we take into the account of embodied emission in the consumption of electricity assuming most of the grid power is generated by the thermal power stations elsewhere in the country, the resultant net CO2 emission estimates from electricity sector are almost same as that of the Kolkata where most of the power is generated by the thermal power stations situated in-side the city's area. The direct CO2 emissions are more in Delhi because of the higher consumption of petroleum products in Delhi. The emission related to steel and cement consumptions are found to be more in Kolkata than Delhi because the calculations are based on the per-capita consumption of these materials. Transport sector is one of the major consuming sectors of petroleum and thus is a contributor of greenhouse gases. This sector has even more importance for the emission of polluted gases like NOx, SO2, CO, particulate matter etc. into the atmosphere. It has been estimated that motor vehicles contribute to about 64% of the pollution in Delhi while other sources (e.g. domestic-8%, industries 12%, power plants - 16%) are of much lesser contributions. These gases play active role in the atmospheric chemistry and are responsible for climate change, adverse effects on human and plant health, atmospheric corrosion etc. The growth of the vehicle population in India has been extremely fast especially in the post economic liberalization era and the number of vehicles has nearly doubled during the 1991-98 period from about 21 millions to about 41 millions5. The Indian mega-cities have also reported large growth rates in the increase in vehicle population as reflected in Table 4-4-7-2.   It has been estimated that the CO emissions from gasoline consumption has increased from 130 Gg (Giga gram which is equal to thousand tons) in 1990-91 to 164 Gg in 1995-96 while from diesel it has increased from 22 Gg in 1990-91 to 35 Gg in 1995-96. The NOx has increased from 3.5 to 4.5 Gg, hydrocarbon from 4.9 to 6.3 Gg, particulate from 0.7 to 0.9 Gg, black carbon from 0.05 to 0.06 Gg and organic carbon from 0.25 to 0.3 Gg from 1990-91 to 1995-96 period in Delhi from Gasoline consumption. From diesel consumption, CO has increased from 22 to 35Gg, NOx from 8 to 12.8Gg, hydrocarbon from 2 to 3Gg, particulate matter from 1.8 to 2.8Gg, black carbon from 7.3 to 11.5Gg and organic carbon from 3.7 to 5.8 Gg during the above-mentioned period in Delhi. In Kolkata, the gasoline consumption's contribution in CO has increased from 12 Gg in 1990-91 to 16Gg in 1995-96, in NOx from 0.3 to 0.4, in hydrocarbon from 0.5 to 0.6, in particulate matter from 0.06 to 0.08, in black carbon 0.005 to 0.006, in organic carbon from 0.02 to 0.03 Gg respectively during this period. The diesel consumption in Kolkata has contributed in CO from 7 to 9Gg, in NOx from 2.6 to 3.2, in hydrocarbon from 0.6 to 0.8, in particulate matter from 0.6 to 0.7, in black carbon 2.36 to 3, and in organic carbon from 1.2 to 1.5 Gg respectively during this period. The transport sector in India is witnessing a rapid transition phase due to several policy interventions related to emission norms for vehicles and quality of fuel supplied. One of the interesting aspects is that most of these interventions have been conceived due to the deteriorated status of ambient air quality caused by pollutants in Delhi due to transport sector. The vehicle fleet in Metro manila is also increasing very fast due to increased demand. It has increased from about 0.4 millions in 1981 to about 1.2 millions in 2002 while the vehicle population in Philippines has increased from about 0.9 millions to about 3.6 millions during this time (Figure 4-4-7-3). The average annual growth rate in the vehicle registration in Metro Manila has been recorded as 6.9% while for Philippines it is 7.8%. The total share of the Metro manila's vehicle in the country total is about 41% during this period although it has decreased from about 44% to 35%. However, certain type of vehicles have larger share in the country total, e.g. gasoline fueled cars in Metro Manila are almost 70% of the cars in the country. But the number of gasoline fueled vehicles in the region is decreasing while those of diesel fueled are increasing. The consequent estimated emissions of particulate matter (PM), SO2, HC, NOx, Pb, CO and CO2 from the transport sector in Metro Manila is given in Figure 4-4-7-4.   The CO2 emission from the consumption of electricity in the Metro Manila has also been estimated. The total consumption of electricity has gone up from 6,825 GWh in 1981 to 14,924 GWh in 2000 in Metro Manila (Figure 4-4-7-5). The average growth rate in overall consumption has been recorded to be about 4.8% but different sectors have witnessed different average growth rate, e.g. it is 5.35% for commercial, 5.1% for residential, 3.7% for industrial and 2.5% for street lighting. The CO2 emissions also show the similar pattern (Figure 4-4-7-6) from electricity consumption in Metro Manila. The average annual growth rates for CO2 emission from total consumption is 6.4% while from consumption in residential sector, it is 6.7%, 6.9% for commercial sector, 5.3% for industrial sector and 4.1 % for consumption in street lighting. Total CO2 emission has been estimated to have increased from 3.5 Tg/yr in 1981 to about 9 Tg/yr in 2000 from electricity consumption in Metro Manila.   (3) Emission Status in Indian Mega-cities The per-capita emissions as calculated from the estimates based on direct as well as embodied sectors are given in Table 4-4-7-3. The CO2 and CH4 estimation have been made for both direct and embodied emissions for Delhi and Kolkata while for other species like CO, NOx, hydrocarbons (HC), particulate matter (PM), black carbon (BC) and organic carbon (OC), mostly transport sector has been taken into consideration. The per capita emissions for most of the species calculated here are found to be higher in Delhi compared to Kolkata's average per-capita emissions. However, the comparison of percentage increases in emissions of short lived gases and particulate matter during 1990-95 periods reveals that percentage increase in per capita emissions of these gases and particulate matter have lower values for Delhi and Kolkata compared to percentage increase in national per capita emissions. The higher population density of these mega-cities compared to the nation is probably responsible for this observation. Interestingly, the percentage increase in emissions of few of the species like particulate, BC and OC in Delhi are almost as high as that of percentage increase in national emission which shows that the fuels like diesel has been consumed in Delhi in larger proportions. A comparison of per-capita CO2 emissions from Delhi, Kolkata and India are given in Table 4-4-7-4 with population . Delhi and Kolkata having 2.4% of Indian population in 1990 have been estimated to have contributed about 5% to the national total CO2 emissions for 1990, 5.2% in 1995 (population share 2.7%) and 4.7% in 2000 (population share 2.9%). For methane, these cities together contributed to about 2.5% of the national total for methane emission in 1990. The ratio of per capita emissions to per capita income, which is a masure of carbon intensity, in Delhi and Kolkata with respect to India shows that while Kolkata's trend is almost similar to that of Indian trend, Delhi has slight difference during 1990-95 period (figure 7). The value decreases from 124.4 in 1990 to 75.1 for India in 1995 and from 124.3 to 77.8 for Kolkata, it decreases from 137.2 to 75.8 for Delhi.    (4) Future Projections for emissions in Delhi & Kolkata Based on the growth rates of per-capita emissions and population, future projections for emissions of CO2, CO, CH4, NOx, hydrocarbon, Particulate matter, black carbon and organic carbon have been made for Delhi and Kolkata assuming the same growth rate as observed during 1990-1995 period and shown in Figures-4-4-7-8a, 8b and 9. Loulou et al.7 have considered three scenarios in macro-economic growth in India for their projections by MARKEL model. These three scenarios are high, medium and low growth scenarios, which were based on observed GDP trends and the future scenarios constructed by some other studies8,,9. The base assumptions for these scenarios are as follows:
 (5) Policy interventions It is evident that the mega-cities have significant contribution in the national emission for most of the gases. Mega-cities also provide a platform to launch concentric targeted efforts to mitigate emissions of pollutants and greenhouse gases which would not only result in the reduction of national emissions but also would bring benefits at local scale like improvement in human health. Increasing awareness about the impact of pollutants on health as made this issue an urgent public agenda putting pressure on the policy makers to devise appropriate policies. In India, a road map has been devised for transport sector to control vehicular emissions which envisaged gradual tightening of emission norms forcing vehicle manufacturer to use latest technologies and improvement of fuel. In addition, program has also launched to have improved road network for better traffic management. In India, the lead (Pb) was totally eliminated from gasoline in 2000 but in Delhi, unleaded gasoline was introduced in 1994. The ambient measurements in Delhi have confirmed the reduction of lead in ambient air in Delhi (Figure 4-4-7-11) but the concentrations of benzene in ambient air (Figure 4-4-7-12) is going up (source: Central Pollution Control Board News Letter, 2002) since then due to various additives added to gasoline as anti-knocking agents in gasoline in place of lead tetra acetate, which should now be tackled properly.   A number of measures have already been implemented in Delhi in transport sector. For example, The entire bus fleet for public transport in Delhi is now running on compressed natural gas (CNG) to improve the city's ambient air. In general most of the Indian cities have shown high suspended particulate matter (SPM) concentrations in ambient air. Recently (since December 2002), Metro train has also been introduced in Delhi and as per our estimates after the completion of its first and second phase in 2005 when it will run on 51 km track, it could result in the annual saving of 124 million tons of CO2, 7 million tons of CO and 7 million tons of particulate matter. Kolkata is the first city in India where Metro train is already in operation. In 1998, it was covering a distance of 16 km which, on the basis of similar assumptions as that of Delhi, shows an annual saving of 41 million tons of CO2, 2 million tons of CO and 2 million tons of particulate matter. References:
 |
