The World Health Organization (WHO) has identified four Indian cities among the ten most polluted in the world based on particulate matter levels. Gwalior, Allahabad, Patna, and Raipur feature prominently in the list, with Delhi ranking 11th.
Particulate matter, particularly PM2.5, is a Group 1 carcinogen linked to stroke, heart disease, lung cancer, and respiratory illnesses. The WHO estimates over seven million premature deaths annually due to air pollution, with three million attributed to outdoor air quality.
The study analyzed data from 3,000 cities across 103 countries, collected between 2008 and 2013. However, some nations lacked monitoring systems, potentially excluding the most polluted areas. Maria Neira of WHO commended India's national plan to address the issue, noting that some cities with severe pollution may not have adequate monitoring for accurate ranking.
The highest PM2.5 level was recorded in Zabol, Iran, at 217 micrograms per cubic metre, compared to Delhi's annual average of 122.
