New study: PM2.5 air pollution in India leads to 1.5 million deaths a year

A groundbreaking study links PM2.5 pollution to 1.5 million annual deaths in India, urging nationwide action to tackle the health crisis caused by poor air quality

PM2.5 levels exceeding the World Health Organization’s (WHO) recommended annual average of 5 micrograms per cubic metre are associated with 1.5 million deaths annually in India, according to a new study by the Consortium for Climate, Health, and Air Pollution Research in India (CHAIR-India).

 

Published in The Lancet Planetary Health, the study reveals that previous estimates of pollution-related deaths in India were significantly underestimated and calls for comprehensive measures to reduce PM2.5 levels.

 

Study background

CHAIR-India, a global consortium of academic institutions, includes key contributors such as Ashoka University’s Centre for Health Analytics Research and Trends (CHART), Karolinska Institutet (Sweden), Harvard University (USA), and Ben-Gurion University (Israel).

 

 

The study used a machine learning-based spatio-temporal model to estimate PM2.5 concentrations across 1,056 locations in India. These were then correlated with district-level mortality data from 2009 to 2019.

 

What is PM2.5?

PM2.5 refers to fine particulate matter that measures 2.5 micrometres or smaller in diameter. These tiny particles, comprising dust, soot, smoke, and liquid droplets, can penetrate deep into the lungs and bloodstream, leading to:

• Respiratory and cardiovascular issues
• Lung cancer
• Asthma

Sources of PM2.5 include vehicle emissions, industrial activity, crop burning, and natural phenomena like dust storms. 

Widespread exposure across India

The study revealed that all 1.4 billion Indians live in areas where PM2.5 levels exceed WHO guidelines.

 

“Delhi may get the headlines, but this is a problem all over India. Nationwide efforts are needed,” said Joel Schwartz, professor at Harvard T.H. Chan School of Public Health and principal investigator from the US for the CHAIR-India consortium.

 

The research also highlighted that incremental risks of mortality are higher at lower PM2.5 concentrations, underscoring the need for interventions even in relatively less polluted regions.

 

Mortality risks and statistics

A 10 micrograms per cubic metre increase in PM2.5 is linked to an 8.6 per cent rise in mortality risk. 

Between 2009 and 2019, 25 per cent of annual deaths (1.5 million) were attributed to PM2.5 levels exceeding WHO limits.

Approximately 0.3 million annual deaths were caused by PM2.5 exposure above India’s National Ambient Air Quality Standards (NAAQS). 

“High PM2.5 exposure levels in India cause a significant mortality burden, not limited to urban areas. A systematic, not symptomatic, approach is needed,” said Suganthi Jaganathan, doctoral researcher at Ashoka University’s CHART.

 

Policy recommendations

The study highlights the urgent need for nationwide air quality management strategies, including:

1. Strengthening regulations and enforcing WHO-compliant air quality guidelines.

2. Addressing high-pollution sources such as coal-burning power plants and crop burning.

3. Expanding efforts to rural areas, which are often overlooked in air pollution control policies.

 

“This nationwide analysis brings critical evidence to policymakers about the severe health impacts of air pollution in India. Mortality is evident at PM2.5 levels far below current Indian standards, which is alarming,” said Petter Ljungman, associate professor at Karolinska Institutet and principal investigator for the CHAIR-India consortium.