By comparison with China, India, which also has densely populated cities grappling with similar levels of pollution, had 620,000 premature deaths in 2010 because of outdoor air pollution, the study found. 
The study was led by an institute at the University of Washington and several partner universities and institutions, including the World Health Organization.
Calculations of premature deaths because of outdoor air pollution are politically threatening in the eyes of some. (NYT, 4/2/2013)