According to the Forbes magazine Mumbai and Delhi are among the 25 dirtiest cities in the world while the four Indian metros and Banglore are among the 20 densest cities.
While Mumbai as the seventh dirtiest and Delhi is at No. 24 fares little better but gets drubbing for the pollution in Yamuna river, which is devoid of marine life and where garbage and sewage flow freely.
The top as the dirtiest city in the world is taken by Baku in Aazerbaijan, suffering life-threatening levels of air pollution emitted from oil drilling. In neighbouring Bangladesh, Dhaka, with lead-poisioned air and water pollution from pesticide use of being the second dirtiest city in the world.
In an earlier Forbes list of the 20 densest urban areas in the world, Mumbai and Kolkata occupied the top two positions, in over 23,000 people per square kilometer while Chennai is at No.8, Delhi at No. 13 and Banglore at No. 19 in the list densest population cities. Karachi in Pakistan is at No. 3.