Impact of growing urbanization and air pollution on the regional climate over India India has witnessed an explosive growth of population (0.3 billion in the year 1950 to 1.04 billion in the year 2002) accompanied by uncontrolled urbanization over the last five decades (www. censusindia.net/, Fig. 1). The population growth has been mainly centered around cities due primarily to the large scale migration of rural population, accelerated by high population growth rates especially in Indo-Gangetic (IG) basin. The result is the IG basin is one of the largest and most densely populated regions of the world (Fig. 2). 9000 8000
Delhi Kanpur Kolkata Nagpur Mumbai
Ganga Basin 0 - 50 51 - 100 101 - 250 251 - 500 1,001 - 122,755
5000 4000 3000 2000 1000 0 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 1950 1955 1960
Population density 2000
70°E 80°E 90°E
Figure 2. Population density (persons/km2) over India (year 2000). In the northern Indian plains, the Ganga (IG) basin, have a very high population density. Rapid industrialization and population growth especially in the last decade have adversely affected urban climate, air quality and caused imbalances in the regional climate at large. Impacts are increasingly visible on the hydrological cycle, agriculture, the energy budget of earth in the form of irregular rainfall distribution, and the monsoon resulting in an increase in the frequency of droughts and floods (Gadgil, 1995; Zhu and Houghton, 1996; Lal et al., 1996a,b; Ramanathan et al., 2001; Menon et al., 2002). Air quality has degraded to moderate to critical levels in major Indian cities with increases in the consumption of fossil fuel (coal and petroleum) especially in transportation sector, thermal power plants, smelters, industries etc. Satellite and ground based indicators of air pollution show disturbing trends that can explain visible changes in the environment. A brief discussion is presented here of the degradation in air quality in major cities, the source of the pollutants and their impact on the environment.
4000 3500 3000 2500 2000 1500 1000 500 0
Asia Urban Asia Rural Asia Total
1950 1955 1960
1965 1970 1975 1980 1985
1990 1995 2000 2005 2010 2015
Total Urban Non-Agr Pop
Rural Agr Pop
0.6 0.4 0.2 0 1961 1966 1971 1976 1981 1986 1991 1996 2001
Figure 1. Urban and rural population growth (in millions) for the World (top), for Asia since 1950 (middle) and for India (bottom), including the Total, Rural, Urban, Agricultural population growth since 1961 (Agr Pop) and non-agricultural population (Non-agr Pop)).
2020 2025 2030
Urban Rural Total
501 - 1,000
Industrialization, growing population and energy demand Population growth has been much higher in the Asian region than globally (Fig. 1). The population density (people/km2) in the year 2000 was 306.9. Rates of urban population growth are higher than those for the rural population primarily due to migration to the cities (Fig. 1). The average annual population growth rate (1980-2000) has been 1.9% (1.6% in the rural areas and 3% in the urban areas). In India, the urban:rural population was 0.181:0.818 (year 1961), 0.742:0.257 (year 1991) and 0.716:0.283 (year 2001). With the increasing population and industrialization, energy demand is increasing and India now stands next to USA, Europe and China in terms of total energy consumption (Fig. 3). Increase in energy needs, along with decreasing dependency on traditional sources of energy (like biomass) especially in the rural sector, has put additional pressure on non-renewable sources of energy like coal and petroleum. In the last decade...