Bathinda: A new Study Published in Lancet Planetary Health finds that even the level air pollution The current Indian Air Quality Standards are below normal due to daily increase in death rate Air pollution rates in India. The study examined 10 Indian cities (Ahmedabad, Bengaluru, Chennai, Delhi, Hyderabad, Kolkata, Mumbai, Pune, Shimla and Varanasi) and found that 33,000 deaths each year are caused by air pollution levels that exceed WHO guidelines. Notably, significant deaths also occurred in cities that are not typically associated with high air pollution. The authors analyzed PM2.5 exposure To arrive at these conclusions, data and daily mortality rates from 2008 to 2019 were studied.
According to the study, 7.2% of the total deaths (about 33,000 per year) across all 10 cities could be linked to short-term PM2.5 exposures above the WHO guideline value of 15 μg/m3. Also, every 10 μg/m3 increase in short-term PM2.5 exposure was associated with a 1.42% increase in daily deaths. When we used a causal modelling approach that excluded the effect of local sources of air pollution, this estimate nearly doubled to 3.57%. The risk of death increases sharply at low PM2.5 concentrations and decreases at higher levels, with significant effects observed even below the current national ambient air quality standard of 60 μg/m³ for 24-hour exposure.
This groundbreaking study provides new understanding of air pollution and health in India. It is the first multi-city study to assess the relationship between short-term air pollution exposure and mortality across different air pollution levels and agro-climatic zones.
The study uses novel causal modelling techniques that isolate the impact of increasing local sources of air pollution, such as waste burning and vehicle emissions.
The results suggest that national air quality standards should be made more stringent and efforts to control air pollution should be intensified. The study was carried out by researchers from several institutions, including Ashoka University, the Center for Chronic Disease Control, Karolinska Institutet, Harvard University and Boston University, many of which are part of the CHAIR-India consortium.
The study also provides important policy insights, highlighting that air pollution policy should be extended beyond ‘non-attainment cities’ that fail to meet Indian standards. These standards are four times higher than the WHO guideline value of 15 μg/m³, leaving many more areas vulnerable. The findings emphasize the need to expand remedial actions beyond the currently designated ‘non-attainment cities’.
The study highlights the need for action on air pollution year-round, not just during seasonal extremes. A significant risk of mortality occurs at low to moderate PM2.5 levels, while the risk decreases at higher levels. Existing policies such as the Graded Response Action Plan primarily target extreme pollution levels and should be readjusted to continuously address air quality throughout the year.
The study also helps develop policy tools to effectively address dispersed local sources of air pollution, which are complex but critical for health improvement. These sources regularly affect most people and require focused attention beyond ambient concentrations. Targeting these everyday exposure sources would yield significant health benefits.
Dr. Bhargav Krishna, Fellow at the Sustainable Futures Collaborative and lead author of the study, said, “The results of this first-of-its-kind multi-city study show us that reducing air pollution is a nationwide challenge. Our analyses show that even cities previously considered less polluted, such as Mumbai, Bengaluru, Kolkata and Chennai, have significant impacts on mortality due to air pollution. The significant impacts observed below current Indian standards have implications for what we consider acceptable air quality, and emphasize the need for strong year-round action across the country.”
Dr. Jeroen de Bont, postdoctoral researcher at Karolinska Institutet and lead author, emphasizes the importance of our first multi-city study. “By combining data from 2008 to 2019 across India’s largest cities, our findings support the view that around 7.2% of India’s largest cities are home to the largest urban centres. Deaths in India “Daily PM 2.5 is the main contributor to air pollution. As efforts to tackle air pollution intensify, it is important to tackle local sources along with existing strategies,” he said.
“This unique study covers air quality variations across 10 Indian cities and demonstrates for the first time that even the lowest levels of air pollution have significant mortality risk. This information signals an urgent need to rethink our air quality management strategies that currently focus only on ‘non-attainment cities’, reconsider current air quality standards for lower exposure limits and shift from addressing regional sources to addressing local sources to effectively protect human health”, said Dr. Poornima Prabhakaran, Director, Centre for Health Analytics Research and Trends (CHART) at Trivedi School of Biosciences, Ashoka University and India Lead of the CHAIR-India Consortium.
“The air pollution levels we see in India are indeed very high and this study clearly shows how day-to-day changes in these levels lead to a significant increase in mortality. Interestingly, we observed that local pollution sources are likely to be more toxic than more distant sources, which has implications for policymakers dealing with this highly relevant threat to human health,” said Dr. Petter Ljungman, Associate Professor at Karolinska Institutet and one of the researchers involved in the study.
Harvard University professor Joel Schwartz, co-author of the study, said, “Reducing and enforcing Indian air quality standards would save thousands of lives each year. Methods to control pollution exist and are used elsewhere. They need to be implemented in India immediately.”
According to the study, 7.2% of the total deaths (about 33,000 per year) across all 10 cities could be linked to short-term PM2.5 exposures above the WHO guideline value of 15 μg/m3. Also, every 10 μg/m3 increase in short-term PM2.5 exposure was associated with a 1.42% increase in daily deaths. When we used a causal modelling approach that excluded the effect of local sources of air pollution, this estimate nearly doubled to 3.57%. The risk of death increases sharply at low PM2.5 concentrations and decreases at higher levels, with significant effects observed even below the current national ambient air quality standard of 60 μg/m³ for 24-hour exposure.
This groundbreaking study provides new understanding of air pollution and health in India. It is the first multi-city study to assess the relationship between short-term air pollution exposure and mortality across different air pollution levels and agro-climatic zones.
The study uses novel causal modelling techniques that isolate the impact of increasing local sources of air pollution, such as waste burning and vehicle emissions.
The results suggest that national air quality standards should be made more stringent and efforts to control air pollution should be intensified. The study was carried out by researchers from several institutions, including Ashoka University, the Center for Chronic Disease Control, Karolinska Institutet, Harvard University and Boston University, many of which are part of the CHAIR-India consortium.
The study also provides important policy insights, highlighting that air pollution policy should be extended beyond ‘non-attainment cities’ that fail to meet Indian standards. These standards are four times higher than the WHO guideline value of 15 μg/m³, leaving many more areas vulnerable. The findings emphasize the need to expand remedial actions beyond the currently designated ‘non-attainment cities’.
The study highlights the need for action on air pollution year-round, not just during seasonal extremes. A significant risk of mortality occurs at low to moderate PM2.5 levels, while the risk decreases at higher levels. Existing policies such as the Graded Response Action Plan primarily target extreme pollution levels and should be readjusted to continuously address air quality throughout the year.
The study also helps develop policy tools to effectively address dispersed local sources of air pollution, which are complex but critical for health improvement. These sources regularly affect most people and require focused attention beyond ambient concentrations. Targeting these everyday exposure sources would yield significant health benefits.
Dr. Bhargav Krishna, Fellow at the Sustainable Futures Collaborative and lead author of the study, said, “The results of this first-of-its-kind multi-city study show us that reducing air pollution is a nationwide challenge. Our analyses show that even cities previously considered less polluted, such as Mumbai, Bengaluru, Kolkata and Chennai, have significant impacts on mortality due to air pollution. The significant impacts observed below current Indian standards have implications for what we consider acceptable air quality, and emphasize the need for strong year-round action across the country.”
Dr. Jeroen de Bont, postdoctoral researcher at Karolinska Institutet and lead author, emphasizes the importance of our first multi-city study. “By combining data from 2008 to 2019 across India’s largest cities, our findings support the view that around 7.2% of India’s largest cities are home to the largest urban centres. Deaths in India “Daily PM 2.5 is the main contributor to air pollution. As efforts to tackle air pollution intensify, it is important to tackle local sources along with existing strategies,” he said.
“This unique study covers air quality variations across 10 Indian cities and demonstrates for the first time that even the lowest levels of air pollution have significant mortality risk. This information signals an urgent need to rethink our air quality management strategies that currently focus only on ‘non-attainment cities’, reconsider current air quality standards for lower exposure limits and shift from addressing regional sources to addressing local sources to effectively protect human health”, said Dr. Poornima Prabhakaran, Director, Centre for Health Analytics Research and Trends (CHART) at Trivedi School of Biosciences, Ashoka University and India Lead of the CHAIR-India Consortium.
“The air pollution levels we see in India are indeed very high and this study clearly shows how day-to-day changes in these levels lead to a significant increase in mortality. Interestingly, we observed that local pollution sources are likely to be more toxic than more distant sources, which has implications for policymakers dealing with this highly relevant threat to human health,” said Dr. Petter Ljungman, Associate Professor at Karolinska Institutet and one of the researchers involved in the study.
Harvard University professor Joel Schwartz, co-author of the study, said, “Reducing and enforcing Indian air quality standards would save thousands of lives each year. Methods to control pollution exist and are used elsewhere. They need to be implemented in India immediately.”
