Saurabh
This is data from 2015. Not only do South Indian cities excel on most socio-economic indexes, they lead India on the pollution indices as well. Before you get too excited, my friends, let me remind you that the factors at play here are more than human.

Chennai, for example, benefits from its daily sea breeze. The breeze keeps the averages really low, but the peaks during commute hours are still as high as any other city. Bangalore is plagued by CO and ozone, almost entirely coming from traffic congestion. Even though PM2.5 levels are low, we have all heard about the persistent pollen and allergen issues in Bangalore.

A lot of people, especially those like me who once volunteered for it, have differences with Greenpeace over the methods it adopts. But this is remarkable work. Greenpeace is one of those rare NGOs that received my donation money, not just my time.