According to the report, 480 million people in northern India are exposed to the "world's most acute levels of air pollution," which have spread to other parts of the country over time.
It goes on to say that strong clean air policies can add up to five years to people's lives.
Every year, more than a million people are killed by filthy air in Indian cities, which consistently top worldwide pollution rankings.
According to a survey by the University of Chicago's Energy Policy Institute (EPIC), north India has "pollution levels 10 times worse than anywhere else on the planet."
It goes on to say that air pollution has moved beyond the region to western and central Indian states like Maharashtra and Madhya Pradesh, where the average individual is now losing two and a half to three years of life expectancy compared to the early 2000s.
According to new statistics from EPIC's Air Quality Life Index research, inhabitants in Delhi might gain up to ten years if air pollution is lowered to the WHO's 10 g/m3 limit.
India had the highest average particulate matter concentration in the world in 2019, at 70.3 g/m3.
Bangladesh, India, Nepal, and Pakistan, which together account for about a quarter of the global population, are consistently ranked among the top five most polluted countries on the planet, according to the research.
EPIC applauds the Indian government's efforts to combat air pollution, such as the 2019 National Clean Air Programme (NCAP), which aims to improve air quality.
"Achieving these targets would have a significant influence on Indians' life expectancy levels," it adds, "increasing national life expectancy by approximately two years and inhabitants of Delhi by three and a half years."
China, according to the study, is an example of how good regulation may result in "dramatic reductions in pollution in a short period of time." Since 2013, the country's particle emissions have decreased by 29%.