Short-Term Exposure to Air Pollution Causes 33,000 Deaths Annually in India: Report

Historical Context: Air pollution has been a growing concern globally, particularly in rapidly developing countries like India. The industrial revolution in the 18th and 19th centuries marked the beginning of significant air pollution issues, but it wasn’t until the latter half of the 20th century that the health impacts of air pollution became widely recognized. In India, rapid urbanization and industrialization post-independence have exacerbated air quality issues, leading to severe health consequences.

Article: A recent study published in Lancet Planetary Health reveals that nearly 33,000 deaths annually in 10 major Indian cities are linked to air pollution levels that are below India’s national clean air threshold. The study underscores the urgent need for India to align its air quality standards with the World Health Organization (WHO) guidelines to safeguard public health.

India’s current clean air norms are significantly higher than the WHO guideline of 15 micrograms per cubic meter of air. The study suggests that India must adopt stricter air quality standards to mitigate the health risks associated with polluted air.

Researchers analyzed data on PM2.5 exposure and daily mortality counts from 2008 to 2019 across 10 cities: Ahmedabad, Bengaluru, Chennai, Delhi, Hyderabad, Kolkata, Mumbai, Pune, Shimla, and Varanasi. The findings indicate that even air pollution levels below the current Indian standards lead to increased daily mortality rates.

Key findings include:

• Delhi: Recorded the highest number of air pollution-related deaths, with 12,000 deaths annually (11.5% of all deaths) linked to PM2.5 exposure above WHO guidelines.
• Varanasi: Logged the second-highest number of deaths, with 830 deaths annually (10.2% of all deaths) due to PM2.5 exposure above WHO guidelines.
• Other Cities: Significant deaths were also recorded in Mumbai (5,100), Kolkata (4,700), Chennai (2,900), and Bengaluru (2,100) annually, all attributable to PM2.5 exposure above WHO guidelines.
• Shimla: Despite having the lowest air pollution levels, 59 deaths annually (3.7% of all deaths) were linked to PM2.5 exposure above WHO guidelines, indicating no safe level of air pollution.

The study is the first multi-city analysis in India to assess the relationship between short-term air pollution exposure and mortality, covering a diverse range of air pollution concentrations and agro-climatological zones.

Researchers from Sustainable Futures Collaborative, Ashoka University, Centre for Chronic Disease Control, Karolinska Institutet, Harvard, and Boston Universities conducted the study. They observed a steep increase in mortality risk at lower PM2.5 concentrations, with significant effects even below the current National Ambient Air Quality Standard of 60 micrograms per cubic meter for a 24-hour exposure.

Summary in Bullet Points:

• Annual Deaths: Nearly 33,000 deaths in 10 Indian cities linked to air pollution below national clean air threshold.
• WHO Guidelines: India’s air quality standards are higher than WHO’s recommended 15 micrograms per cubic meter.
• Study Period: Data from 2008 to 2019 analyzed for PM2.5 exposure and daily mortality.
• Delhi: Highest number of deaths (12,000 annually) due to PM2.5 exposure above WHO guidelines.
• Varanasi: Second highest (830 deaths annually) due to PM2.5 exposure above WHO guidelines.
• Other Cities: Significant deaths in Mumbai (5,100), Kolkata (4,700), Chennai (2,900), and Bengaluru (2,100) annually.
• Shimla: Lowest pollution levels but still 59 deaths annually due to PM2.5 exposure above WHO guidelines.
• First Multi-City Study: Assessed short-term air pollution exposure and mortality across diverse Indian cities.
• Research Collaboration: Conducted by researchers from multiple institutions including Ashoka University and Harvard.
• Health Impact: Significant mortality risk even below current national air quality standards.