Despite lower levels of air pollution, Bengaluru has higher mortality risk: Study

New Delhi: Air pollution triggers thousands of premature deaths in Indian cities every year even at concentrations of polluting particles below India’s adopted safe limit, researchers have cautioned in a new study, which has also highlighted the large number of such deaths in relatively clean cities like Bangalore and Chennai.

India’s first multi-city evaluation study on the exposure to air pollution reveals nearly 33,000 deaths every year in 10 cities with Delhi topping the list with nearly 12,000 deaths followed by Mumbai (5,091) and Kolkata (4,678)

But worryingly, a significant number of deaths were observed in cities where air pollution is not considered to be a big problem.

Cities like Bengaluru, Hyderabad and Chennai with lower levels of air pollution showed much higher mortality risk, says the study published in the Lancet Planetary Health.

“When we monitor the PM-2.5 level over a 48 hour cycle, we found that an increase of every 10 microgram will increase the chances of death by 3% in Bangalore as against 0.3% in Delhi. The risk is ten times more in Bangalore,” Poornima Prabhakaran, director of the Centre for Health Analytics and Research at Ashoka University and one of the lead members of the study team, told DH.

The ten cities included in the study are Ahmedabad, Bengaluru, Chennai, Delhi, Hyderabad, Kolkata, Mumbai, Pune, Shimla and Varanasi.

The researchers from India, Sweden and USA found that over a 12 year period between 2008 and 2018, more than 7 per cent of all deaths across 10 cities could be linked to short-term PM-2.5 exposure higher than the WHO guideline value of 15 micrograms per cubic metre.

The WHO ceiling of the pollutant’s safe limit was much lower than the Indian standard (40 micrograms annually). But worryingly, the study found high levels of air pollution deaths in cities where the annual PM-2.5 limit is below the Central Pollution Control Board standards.

For instance Bangalore with an annual PM-2.5 level at 33 micrograms per cubic metre has an estimated 2,102 air pollution related deaths. Similar mortality numbers for Chennai (PM-2.5 at 33.7 micrograms) is 2,870 while for Ahmedabad (37.9) it is 2,495. For Hyderabad (38.9) it is 1,597 and even for a hill station like Shimla (28.4), there are 59 air pollution related deaths.

“The study shows a significant number of air pollution related deaths in so-called cleaner cities and the threshold values for air quality standards need to be revisited,” Prabhakaran said.

The Union Environment Ministry runs the National Clean Air Programme in 131 non-attainment cities where air pollution levels — such as PM2.5 concentrations — have exceeded the NAAQS values for five years to combat air pollution.

“The risk of mortality is high in these cities. We need to identify the regional and local sources of pollution and greater focus should be on dispersed local sources of air pollution including transport, waste burning and diesel generator sets,” Prabhakaran said.

Flagging the seriousness of the study findings, former Union Environment Minister and Congress leader Jairam Ramesh said, “The NCAP, launched in 2019 with typical fanfare, has turned out to be a complete failure. More than 50% of NCAP funds were not utilised by the end of 2023. Further, as the Lancet study points out, the clean-air targets set by the NCAP are much too low to save lives.”

“Out of 131 cities under NCAP, most do not even have data to track their air pollution. Of 46 cities which have data, only 8 cities have met the NCAP’s low target, while 22 cities actually saw air pollution get worse,” he added.

The researchers pointed out that actions against air pollution have to be taken round-the-year and all over the country rather than focussing primarily on the Indo-Gangetic plains and that too in the winter.

“But since 2017, the Modi Government has continuously pushed back the deadline for coal power plants to install pollution-controlling Flue Gas Desulphurisation (FGD) equipment. It has led to thousands of deaths, all for the profit of plant owners,” Ramesh said.