Air pollution in India is quite a serious issue with the major sources being fuelwood and biomass burning, fuel adulteration, vehicle emission and traffic congestion. In autumn and winter months, large scale crop residue burning in agriculture fields – a low cost alternative to mechanical tilling – is a major source of smoke, smog and particulate pollution. India has a low per capita emissions of greenhouse gases but the country as a whole is the third largest after China and the United States. A 2013 study on non-smokers has found that Indians have 30% lower lung function compared to Europeans.
Most Indian cities greatly exceed acceptable levels of suspended particulate matter. ... Of the four majorIndian cities, air pollution was consistently worse in Delhi, every year over 5-year period (2004–2008). Kolkata was a close second, followed by Mumbai. Chennai air pollution was least of the four.