22 of world's 30 most polluted cities are in India, Greenpeace says

Analysis of air pollution data finds that 64% of cities globally exceed WHO guidelines

Twenty-two of the world's 30 worst cities for air pollution are in India, according to a new report, with Delhi again ranked the world's most polluted capital.

The Greenpeace and AirVisual analysis of air pollution readings from 3,000 cities around the world found that 64% exceed the World Health Organization's annual exposure guideline for PM2.5 fine particulate matter - tiny airborne particles, about a 40th of the width of a human hair, that are linked to a wide range of health problems.