Prolonged exposure to pollution contributed to millions of deaths across India over a decade, according to a new study that called for stricter air quality regulations.
The study, published in The Lancet Planetary Health, assessed the link between tiny air pollution particles and mortality between 2009 and 2019 across hundreds of districts. It warned that there could be high rates of death across the country even at pollution levels below the current national air quality standards.
Researchers from Sweden’s Karolinska Institutet looked especially into the role played by PM2.5, pollution particles less than 2.5 micrometres in diameter that are known to enter the lungs and bloodstream and pose major health risks.
“We found that every 10 micrograms per cubic meter increase in PM2.5 concentration led to an 8.6 per cent increase in mortality,” study lead author Petter Ljungman said.
The researchers statistically analysed the relationship between changes in air pollution levels and death rates across 655 districts.
They found that around 3.8 million deaths from 2009 to 2019 could be linked to air pollution levels staying above India’s air quality guidelines of 40 micrograms per cubic metre.
A maximum PM2.5 exposure of 119 micrograms per cubic metre was measured in Ghaziabad in northern Uttar Pradesh state and the national capital of New Delhi in 2016.
If WHO’s recommended air quality guidelines of 5 micrograms per cubic meter were applied, the mortality figure across India rose to 16.6 million, researchers said.
The study warned that India’s entire population lived in areas where PM2.5 levels exceeded WHO guidelines, meaning that about 1.4 billion people were exposed throughout the year to air pollution that negatively affected their health.
“The results show that current guidelines in India are not sufficient to protect health. Stricter regulations and measures to reduce emissions are of the utmost importance,” Dr Ljungman said.
“Our study provides evidence that can be used to create better air quality policies, both in India and globally.”
The Indian government launched a national air pollution control programme in 2017, the study noted, but PM2.5 concentrations continued to rise in many parts of the country.
“Our results indicated previous data of disease burden from ambient PM2.5 exposure in India are considerably underestimated,” the researchers said.
The study provided the most accurate assessment of the health impact of air pollution in India to date based on state-of-the-art comprehensive exposure assessment and nationwide mortality data, they added.
