Delhi has been ranked the most polluted city in the world as per a global analysis of air quality. The report, Air Quality and Health in Cities, was released by the US-based Health Effects Institute on Wednesday. It analyses pollution and global health effects for more than 7,000 cities around the world. Nigeria’s Kano, Peru’s Lima, Dhaka, Jakarta, Nigeria’s Lagos, Karachi, Beijing and Ghana’s Accra are in the top ten. Mumbai has been ranked 14.
Delhi and Kolkata were ranked first and second in the list of the top 10 most polluted cities
Delhi and Kolkata were ranked first and second in the list of top 10 most polluted cities when PM2.5 levels were compared.
The report summarises data on air pollution exposures and associated health impacts caused by these pollutants. The analyses were done in 7,239 cities between 2010 to 2019. Of these, 1,503 are from South Asia. Moreover, the report used data from satellite imagery and ground measurements. The latter included publicly available data from 3,787 air quality monitoring stations across 63 countries for PM2.5, and 5,220 air quality monitors from across 58 countries for NO2. Notably, Mumbai was ranked 14th. No other Indian city features in the top 20.
Global patterns for exposures to the two key air pollutants were “strikingly different”: Report
In terms of the highest disease burden from a PM 2.5-related ailment, though, Beijing, with 124 attributable deaths per 100,000 people was the worst. Moreover, Delhi came in at 6th, with 106 deaths per 100,000 and Kolkata at 8th with 99. Five Chinese cities were in the top 20.
A large number of global cities across the world exceeded the World Health Organization’s norms for both PM 2.5 and NO2. The report found Delhi’s average PM 2.5 exposure to be 110 micrograms per cubic metre in 2019. It is 22 times the WHO benchmark of 5 micrograms per cubic metre. Kolkata had an average exposure of 84 micrograms per cubic metre.
Shanghai had average NO2 exposure of 41.6 micrograms per cubic metre. It is followed by Moscow in Russia (40.2 micrograms per cubic metre). The WHO standard for NO2 exposure is 10 micrograms per cubic metre. The report said in 2019, exposure to pollutants in 86% of the more than 7,000 cities included in the report exceeded WHO’s standard. Therefore it impacts around 2.6 billion people.
“While PM2.5 pollution tends to get more attention on known hotspots around the world, fewer data has been available for NO 2 at this global scale,” the report notes.
World’s top 20 polluted cities
- Delhi
- Kolkata
- Kano, Nigeria
- Lima, Peru
- Dhaka, Bangladesh
- Jakarta, Indonesia
- Lagos, Nigeria
- Karachi, Pakistan
- Beijing, China
- Accra, Ghana
- Chengdu, China
- Singapore, Singapore
- Abidjan, Cote d’Ivoire
- Mumbai
- Bamako, Mali
- Shanghai, China
- Dushanbe, Tajikistan
- Tashkent, Uzbekistan
- Kinshasa, Democratic Republic of the Congo
- Cairo, Egypt