Statistically, India has some of the world's worst pollution. Air emissions control and other environmental protection methods are behind what some of the other leading nations have implemented and with a large population in a very condensed area, India's pollution is greatly exceeding other parts of the world in that regard.
I think China is probably the worst however. We aren't seeing consistently crazy pics coming out of India like we are China. The pics of the smog in Bejing are just out of this world. I don't know how anyone can even breathe that without immediately dying on the spot.
As sited in The Guardian, a study was conducted by the World Health Organization in 2014. Testing was conducted in 1,600 cities throughout the world. The findings of the study proved Delhi has the worst pollution in the world for PM2.5 particles. These particles may cause severe medical conditions affecting the respiratory and cardiovascular systems.
Serioulsy, I have seen the horrible pollution in China on the news and if India is worse then that it I feel really bad for those who live there. Why, because in China it has gotten to the point where people have to go outside wearing mask at times of days because the pollution is so bad. If India is worse then that I can't see how anyone can live there.