Delhi's poor quality has risen from a local experience to a global reality. The capital has been identified as the World's most polluted city in terms of PM 2.5 level in terms of annual average population as per a global survey on air quality. Kolkota is second on the list while Mumbai is number 14 among the 20 Most Polluted cities in the World.
The report 'Air Pollution and Health in Cities' released by Health Effects Institute’s (HEI) State of Global Air Initiative studied the AQI of 7,239 cities globally. It focuses on two of the most harmful pollutants, fine particulate matter (PM2.5) and nitrogen dioxide (NO 2).
According to the report, of these, 1,503 are from South Asia. The report used data from satellite imagery and ground measurements. Besides India, China’s three cities – Beijing, Shanghai and Chengdu – featured in the list of the World’s top 20 polluted cities.
The report also stated the need for improved local air quality monitoring infrastructure worldwide. Based on the 2022 WHO Air Quality Database, of the 20 cities with the steepest increases in PM2.5 exposures in our data, only two Satna in Madhya Pradesh and Varanasi in Uttar Pradesh in India have an official monitoring station at ground level.