India's high air pollution, ranked by the World Health Organisation among the worst in the world, is adversely impacting the lifespans of its citizens, reducing most Indian lives by over three years, a new study has said.
If India reverses this trend to meet its air standards, those 660 million people would gain about 3.2 years onto their lives, the study said.
Put another way, compliance with Indian air quality standards would save 2.1 billion life-years, it said.
"India's focus is necessarily on growth. However, for too long, the conventional definition of growth has ignored the health consequences of air pollution," said Michael Greenstone, an author of the study and director of the Energy Policy Institute at the University of Chicago (EPIC).
"This study demonstrates that air pollution retards growth by causing people to die prematurely. Other studies have also shown that air pollution reduces productivity at work, increases the incidence of sick days, and raises health care expenses that could be devoted to other goods."
The new figures come after the WHO estimates showed 13 of the 20 most polluted cities in the world were in India, including the worst-ranked city, Delhi.
India has the highest rate of death caused by chronic respiratory diseases anywhere in the world.
"The loss of more than two billion life years is a substantial price to pay for air pollution," said Rohini Pande, also an author and director of Evidence for Policy Design at the Harvard Kennedy School.
"It is in India's power to change this in cost effective ways that allow hundreds of millions of its citizens to live longer, healthier, and more productive lives. Reforms of the current form of regulation would allow for health improvements that lead to increased growth," Pande said.
The authors - who also include Nicholas Ryan of Yale, Janhavi Nilekani and Anish Sugathan of Harvard, and Anant Sudarshan, director of EPIC's India office - offer three policy solutions that would help to cost-effectively decrease India's pollution.
One initial step would be to increase its monitoring efforts and take advantage of new technology that allows for real-time monitoring, the authors said.