New Delhi’s concentration of PM2.5 particles, which damage people’s lungs, is 34 times the World Health Organization’s (WHO) acceptable levels. The toxic haze is especially bad during the winter as farmers burn stubble left in their fields.In 2020, India had 46 of the world’s 100 most polluted cities, followed by China (42), Pakistan (6), Bangladesh (4), Indonesia (1), and Thailand (1), according to air quality tracker IQAir. All these cities had a PM2.5 air-quality rating of more than 50.
Nine out of the top 10 most polluted cities are in India. Hotan, in western China’s Xinjiang, had the worst average air quality in 2020, with 110.2.