Abstract
The city of Varanasi is one of the world’s oldest surviving conurbations being a center of culture and civilization for almost 3000 years. It is a very dense city accommodating more than 2300 inhabitants per square kilometer. Also, it is a major tourist destination attracting more than 6.3 million domestic tourists and one million foreign tourists per year. Unfortunately, it is also one of the fifteen most polluted cities in the world. The average PM2.5 concentrations in 2015 was more than 78.4 ± 10.3 _g/m3, which is twice the national standard and more than 7 times the WHO guideline. This study uses satellite data to acquire a continuous map of the different levels of air pollution throughout the city. The MODIS aqua and terra data are used to obtain the aerosol optical depth(AOD) to assessing the air quality. The result is compared with the in-situ observations for validation of the prediction capability. Also, in order to identify the major contributors of air pollution, the result was correlated with factors like vehicular traffic, industries, vegetation index, population density, etc. Moreover, a spatiotemporal trend of change in pollution levels with the changing land use composition over time is also analyzed. The monthly average AOD concentration over the place for past 3 years were observed to analyze the trend. The various urban activities have been analyzed to assess the major factors contributing to increased levels of PM10, NO2 and SO2 thus giving an insight about ameliorating air quality in Varanasi.
