Contamination of Urban India Environment by Hazardous Industries Material & method Baseline information on land use / land cover of the regions for 1971, were generated from SOI toposheet and compared with IRS-1D LISS-III & PAN data of March 2001 using Land Use classification given by NRSA (1987). Land use and land cover maps of the four study areas were analyzed in ARCGIS and change detection indicating degradation of resource quality was performed. Using slope information the four study areas were delineated into watersheds for assessing flow-path of pollutants and spread of contamination in soil and surface water around the factory site. Normalized differential vegetation index (NDVI) was used to observe vigour of vegetative growth to correlate the impact of contamination. To assess water quality in various surface water bodies, characteristic reflectance curves were generated to establish a relationship between pollution status of a water body and its spectral digital values. Discussion Land Use alterations and Land Cover modifications Alteration and modification of land use and land cover are indicative of processes of change that may lead to positive impact on development or denote resource degradation. Study of these resources using satellite data on a temporal basis would yield information on impact trends. For an insight in this aspect, satellite data from IRS 1D (LISS - III & PAN) were interpreted with older sets of data from IRS –1A / 1B, LANDSAT –TM in conjunction with SOI toposheet to reveal trends in change. Based on this analysis it was found that Hyderabad metropolitan region had changed drastically. While in 1971, agriculture was dominant accounting for 62.6 % area with open scrub, settlement and water bodies accounting for 15, 5.7 and 5.6 % respectively. However, by March 2000 agriculture had lost its preeminence to urbanisation and built-up area accounted for 43% of the study area (Purnend et al 2001). There was a corresponding decrease in area under open scrub (4.2%) and water bodies (2%) and the number of water bodies decreased from 1271 to 960 during the corresponding period. Besides this, catchment of major water bodies in the region, viz., Himayat Sagar, Osman Sagar and Hussain Sagar were severely encroached upon adversely affecting inflow and decreasing dilution potential (Fig.1).  Fig. 1 Change in Land Use/ Land cover and decrease in agriculture (1971 - 2000) in 30 years Similarly, Bangalore metropolitan region witnessed tremendous change in land use and land cover owing to urbanisation and industrialisation. While agriculture was predominant in 1971 (64.82 %), wasteland, built-up area and water bodies occupied 11.8, 5.4 and 3.6 % of the study area, respectively. By March 2000 built-up area increased to 13.3 % of the study area while wasteland and water bodies shrank to 8.6 % and 4.1% respectively. In Chennai, population density increased tremendously during the corresponding period. In 1971 agriculture was dominant with 57.4 % of the study area while open scrub, built-up land and water bodies occupied 7.2, 10.1and 12.8 %. However by March 2001 agriculture was restricted to 43.5 % while built-up area increased to 20.6%. There was a decline in area under open scrub, water body, reserved forest and mud flats along the coastline. |