Three years — those are the number of years that 660 million Indians lose to air pollution. This ground-breaking study was conducted by Michael Greenstone of the University of Chicago and it also engaged revered environmental economists from Yale and Harvard universities and was released on February 21, 2015. By the way, 660 million Indians add up to about half of our population. And the study doesn't stop here.

It also estimated that about 99.5 per cent of India’s 1.2 billion people were breathing air that was unsafe as per World Health Organization's standards. As much as 77 per cent of India's urban areas exceed the national standards of air pollution levels. And guess what? If all of India somehow decided to abide by environmental standards the life expectancy of 660 million people will go up by 3.2 years on average. The gains could range from 1.1 to 5.7 years.

Not only are the air pollution levels shortening our lives, but it is also holding back the economy of India as well. The study also advocated that India's environmental laws, the air and water Acts are in desperate need of revision.  

The study focuses on particulate matter, proven to be dangerous for the health of human beings.