Indians could live about four years longer on average, or a total of more than 4.7 billion life years, if the country complies with World Health Organisation's (WHO) air quality standards, a new study on impact of air pollution on life expectancy has revealed.
And even if only national standards rather than WHO standards are met, Indians could live more than one year longer on an average, says the University of Chicago's Energy Policy Institute (EPI), which has for the first time developed an Air Quality-Life Index (AQLI) to measure how much longer people would live if air pollution was reduced.
According to the AQLI, If India met its own air quality standard for PM 2.5 (40 µg/m³)?every Indian would live an average 1 year more; and if it met the more stringent WHO standards for PM 2.5 (10 µg/m³) Indians would live on average four years longer.
The compliance with WHO standards could see Delhi residents, who breathe the world's most polluted air, gain the most as they could live up to nine years longer and six years more if national standards are met, the study added.
In Kolkata and Mumbai better air quality would translate into almost 3.5 year longer life spans.
''The AQLI is the first tool of its kind to allow people to learn how much longer they could live in the areas where they live if air pollution is reduced to meet global or national standards,''Michael Greenstone, the director at EPI and lead author of the study, said.
''It suggests that particulates are the greatest current environmental risk to human health, with the impact on life expectancy in many parts of the world similar to the effects of every man, woman and child smoking cigarettes for several decades.''
The AQLI was developed on the basis of two studies, published in 2013 and 2017, that analysed the adverse impact of air pollution in China on life expectancy. Using the results from the earlier studies, the AQLI model made projections for Indian districts.
The earlier research studies had analysed almost a decade's data on pollution, respiratory diseases and mortality in China to arrive at a conclusion that heavy air pollution was cutting lifespans by almost 3.1 years in some of China's most polluted regions.
"Life expectancy is very difficult to compute as there are several factors at play. For instance, polluted areas are also often poorer areas so there are different factors affecting health. We have used the models from the China study to make projections and estimate pollution's impact on life expectancy," said Anant Sudarshan, India director at EPIC.
He added, "With rising pollution, there is a rise in respiratory diseases. There have been individual studies on health impacts, but this is the first comprehensive study to look at the net impact of air pollution on life expectancy."
The Ministry of Environment, Forests and Climate Change has in the past denied international reports that air pollution is directly linked to mortality in the country. In February, former environment minister the late Anil Dave had played down the 'State of Global Air' report that said air pollution was causing more premature deaths in India than China.
The estimated average PM 2.5 concentration for population-weighted exposure in India increased from 59 µg/m3 in 1990 to 73 µg/m3 in 2015. The Global Burden of Disease 2015 report estimated that PM 2.5 contributes to 4.2 million deaths globally, a majority of which occur in India and China. The new report presents a different but no less distressing aspect of the problem.