Long-term exposure to fine particulate matter (PM2.5) above the World Health Organization’s (WHO) recommended annual limit of 5 µg/m³ is associated with an estimated 1.5 million deaths each year in India, according to a study published in The Lancet Planetary Health.
Alarming Levels of PM2.5 Pollution
PM2.5 refers to airborne particles with a diameter of 2.5 microns or smaller, a key indicator of air pollution. The study revealed that the entire population of 1.4 billion people in India resides in areas where PM2.5 concentrations exceed the WHO’s guideline. Furthermore, 81.9% of the population (1.1 billion people) live in regions where levels surpass India’s National Ambient Air Quality Standard (NAAQS) of 40 µg/m³.
Study Insights
The research analyzed annual deaths between 2009 and 2019 across Indian districts, using satellite data and ground-based monitoring from 1,056 locations to assess PM2.5 concentrations. Key findings included:
- Wide Variation in Pollution Levels: In 2019, the lowest PM2.5 concentration was 11.2 µg/m³ in Lower Subansiri, Arunachal Pradesh, while the highest was 119.0 µg/m³ in Ghaziabad, Uttar Pradesh, and Delhi in 2016.
- Mortality Risk: A 10 µg/m³ increase in annual PM2.5 levels was linked to an 8.6% rise in annual mortality.
- Estimated Premature Deaths: Between 2009 and 2019, 3.8 million premature deaths were attributed to PM2.5 exposure based on the Indian standard, accounting for 5% of total mortality. Using the stricter WHO guideline, this figure rose to 16.6 million deaths, representing 24.9% of total mortality.
Policy Implications
The authors emphasized the need to revise India’s air quality standards to align more closely with WHO recommendations. “The current NAAQS should motivate policymakers to re-evaluate guidelines without implying that these concentrations are safe,” the paper stated.
Global and National Context
In 2019, the Global Burden of Diseases study attributed 0.98 million deaths in India to ambient air pollution, but this estimate was based on exposure-response data from countries with lower pollution levels. By using India-specific data, the study aimed to provide a more accurate assessment of the impact of PM2.5 pollution on mortality.
Population-weighted mean PM2.5 exposure in India between 2000 and 2019 averaged 57.3 µg/m³, with concentrations increasing significantly after 2010. The WHO revised its air quality guidelines in 2021, lowering the recommended annual PM2.5 limit from 10 µg/m³ to 5 µg/m³, citing evidence of severe health risks even at lower exposure levels.
Call to Action
The findings highlight the urgent need for stronger measures to curb air pollution in India. Addressing the high levels of PM2.5 exposure could prevent millions of premature deaths and improve overall public health outcomes.
