A new study by the Karolinska Institute has revealed that long-term exposure to air pollution is a significant contributor to millions of deaths in India. The research, published in The Lancet Planetary Health, highlights the urgent need for stricter air quality regulations. It reveals that the entire population of India is exposed to PM2.5 levels that exceed WHO guidelines, posing severe health risks to approximately 1.4 billion people. In certain regions, PM2.5 levels have reached as high as 119 micrograms per cubic meter—well above the thresholds considered safe by both WHO and Indian standards.

Despite the government’s efforts to improve air quality through the NAPCP, launched in 2017, the study found that PM2.5 concentrations have continued to rise in several areas. 

In an exclusive interview with First Check, Dr. Suganthi Jaganathan, the study’s lead author, identified the diverse sources of air pollution as residential biomass burning, crop burning, industrial emissions, transport, construction activities, and brick kilns.

“Air pollution is not confined to urban areas; it is a widespread issue, affecting even rural regions,” Dr. Jaganathan said while calling for a review of the National Ambient Air Quality Standards, which have remained unchanged since 2009, as part of the National Air Pollution Control Program (NAPCP).

Excerpts from the interview

Which factors contributed most significantly to the rising PM2.5 levels in India during the study period?

Sources of air pollution include residential biomass burning for cooking and heating purposes, crop burning, industrial emissions, transport, construction activities and brick kilns to name a few. Our study examined the overall effect of air pollution and not specific sources of air pollution so we cannot comment on which sources increased during the study period.

You mentioned in the study that every 10 micrograms per cubic meter increase in PM2.5 concentration leads to an 8.6% rise in mortality. Could you elaborate on the potential long-term health consequences for people exposed to PM2.5 levels that exceed India’s current air quality guidelines, as found in your research?

The 8.6% increase in mortality is due to the long-term exposure to PM2.5 [as we study annual exposure]. The high PM2.5 exposure levels that we see in India could cause respiratory effects, travel to distant organs like heart, brain, and cause chronic inflammation and lead to several health effects among the exposed people. In our study, we estimated an overall of 3.8 million deaths [which is ~300,000 deaths per year] due to annual exposure to PM2.5 above Indian air quality guidelines.

The study indicates that the entire population of India lives in areas where PM2.5 levels exceed WHO guidelines, meaning almost 1.4 billion people are exposed annually to harmful air pollution. Are there any regions that are least impacted, and which areas are the most affected?

Based on the recent WHO guidelines for PM2.5 levels which is 5 microgram per cubic metre, we observed that no district in India has 5 microgram for annual average, the lowest PM2.5 concentration (11 microgram per cubic metre) that we saw was in Lower Subansiri district in Arunachal Pradesh. There could be a few cleaner days or days with lower levels of PM2.5 but not throughout the year, so when we study annual averages, we see exposure in the district throughout the year as long term exposure levels. 

How can India’s current air pollution control program could be improved to effectively reduce PM2.5 concentrations and reduce public health risks?

National air pollution control program must revisit the national ambient air quality standards which have been in place since 2009. Evidence from other parts of the world and now from India indicate there is a high mortality burden even if you consider 40 microgram per cubic metre and make concrete efforts to reduce air pollution levels across the country.

Given that PM2.5 particles can travel hundreds of kilometers, what international collaborations or regional approaches would you recommend to tackle cross-border air pollution?

Air pollution is an ubiquitous problem and PM2.5 can travel for long distances. There needs to be international cooperation and air-shed [geographical area where local topography and meteorology limit the dispersion of pollutants away from the area] based interventions to reduce levels of air pollution for greater public health benefits. However, the local emissions are still very important to control since these fresh particles are considered more toxic, something that we observed indirectly in our previous study also published in the Lancet Planetary Health. So the efforts are needed on several fronts.

What role do you see for public awareness in shifting both local and national attitudes towards stricter air quality regulations in India?

Acknowledging the problem is the first step we can take towards addressing the problem. Then making concrete plans and following through to reduce levels that are practical to India. We can design programs to reach lower levels of air pollution, for example, WHO interim targets.  Public awareness is the most crucial factor for the success of any national program. In this case of air pollution, we require corrective actions from individuals, communities, states and at country level.

What do you think about the dominant idea that air pollution in India is an urban issue?

Air pollution is not localized to cities, it is a widespread problem, seen even in the rural areas. There are far reaching health effects due to air pollution demonstrated across the world and now in India.  Air pollution doesn’t affect only respiratory health, it can cause several cardiovascular problems, kidney problems, reproductive problems, impairs child development to name a few and death.

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