In a latest comprehensive report on the impacts of pollution, The Lancet Planetary Health journal has concluded that on average, 7.2 per cent of all daily deaths in 10 of the largest and most polluted cities in India, are caused by the harmful PM2.5 particles.

The enlisted cities include Delhi, Bengaluru and Mumbai where the PM2.5 levels are reportedly higher than World Health Organization (WHO) guidelines for safe exposure.

About the study conducted by Lancet

The research has been conducted by scholars from Varanasi’s Banaras Hindu University and the Centre for Chronic Disease Control, New Delhi.

The study, "the first multi-city, time series analysis of short-term exposure to PM2.5 and daily mortality in India," looked at roughly 36 lakh daily deaths across ten Indian cities between 2008 and 2019. Other cities included in the analysis were Ahmedabad, Hyderabad, Kolkata, Pune, Shimla and Varanasi.

Lancet report on air pollution: Key findings

• According to the report, Delhi was found to have the largest fraction of daily and yearly deaths attributable to PM2.5 air pollution, caused by particles sized 2.5 micrometres or less in diameter.

• The primary sources of the pollution included vehicular and industrial emissions.

• The extensive study has established the fact that daily exposure to PM2.5 pollution in Indian cities shares a direct link with a higher risk of death, and locally created pollution could be possibly causing these deaths.

• The research indicated that an increase of 10 micrograms per cubic metre in the average of fine particulate matter (PM2.5) pollution measured over two days (short-term exposure) was related to 1.4 per cent higher daily mortality.

• The death risk was found to be doubled (2.7 per cent) per a 10 microgram per cubic metre increase, when the researchers restricted their analysis to observations below Indian standards of air quality, less stringent than WHO guidelines for safe exposure, which prescribe 15 micrograms per cubic metre of PM2.5 over a 24-hour period.

• While studying the city-wise mortality rates, the authors found a 0.31 per cent rise in daily mortality per a 10 micrograms per cubic metre increase in PM2.5 in Delhi, while for Bengaluru, the rise was 3.06 per cent.

• The links between daily exposure to PM2.5 pollution and locally created pollutants were found to be stronger in models which the researchers used to explore cause-and-effect relationships.

  Therefore, it was possible that the locally generated pollutants were causing these excess deaths, the authors said.