‘Delhi ranks No.1’: Delhi tops list of world’s most polluted cities; Kolkata, Mumbai among top 20 

In terms of PM2.5 levels, New Delhi, Kolkata, and Mumbai rank among the top 20 most polluted cities in the world, according to the most recent State of Global Air study on air quality and health in cities. Mumbai is ranked number 14 on the list, behind New Delhi and Kolkata, which is at the first and second place, respectively.

According to the study, fine particulate matter (PM2.5) and nitrogen dioxide are the two main air pollutants that cities were ranked on. PM2.5, or fine particulate matter, is an atmospheric particle with a diameter of less than 2.5 micrometres, or about 3% of the diameter of a human hair. In addition to lowering sight, it affects breathing.

At the same time, one of the main outdoor sources of NO2, whose prolonged exposure is associated with death, is road traffic.

In terms of population-weighted NO2 exposures in 2019, there were no Indian cities among the top 20. The top three cities on this list are Shanghai, Moscow, and Tehran.

The Global Burden of Disease Project of the Institute for Health Metrics and Evaluation and the US-based Health Effects Institute collaborated to produce the Air Quality and Health in Cities report, which was released by the State of Global Air.

According to the research, Kolkata was second with 84 g/m3 and Delhi had 110 g/m3 of population-weighted yearly average PM2.5 exposure in 2019.

Here is the list of the top 20 most polluted cities in the world (PM2.5) with the PM2.5 levels in μg/m3:

1. Delhi, India (110)

2. Kolkata, India (84)

3. Kano, Nigeria (83.6)

4. Lima, Peru (73.2)

5. Dhaka, Bangladesh (71.4)

6. Jakarta, Indonesia (67.3)

7. Lagos, Nigeria (66.9)

8. Karachi, Pakistan (63.6)

9. Beijing, China (55)

10. Accra, Ghana (51.9)

11. Chengdu, China (49.9)

12. Singapore, Singapore (49.4)

13. Abidjan, Côte d’Ivoire (47.4)

14. Mumbai, India (45.1)

15. Bamako, Mali (44.2)

16. Shanghai, China (40.1)

17. Dushanbe, Tajikistan (39.7)

18. Tashkent, Uzbekistan (38)

19. Kinshasa, Democratic Republic of the Congo (35.8)

20. Cairo, Egypt (34.2)