Delhi no more the world's most polluted city; 4 Indian cities still in top 10 of WHO list

According to the latest urban air quality data released by the World Health Organisation on 12 May, Delhi is no longer the world's most polluted city.

In the year 2014, Delhi ranked as number one in the list of 1,600 cities monitored by the WHO.

The National Capital is now 11th on the list of 3,000 cities ranked in terms of PM 2.5 (fine particulate pollution). Delhi's PM 2.5 level is 122.

On the list of cities ranked in terms of PM 10 (coarse pollution particles) levels, Delhi holds the 25th spot.

While Delhi managed to slip 10 places, four Indian cities have found slots in top 10. Gwalior, Allahabad, Patna and Raipur have been placed at second, third, sixth and seventh positions respectively.

Other Indian cities in the top 20 are Ludhiana (12th), Kanpur (15), Khanna (16), Ferozabad (17) and Lucknow (18).

Iran's Zabol is listed as the most polluted city among 3,000 cities across 103 countries. The PM 2.5 level in Zabol is recorded as 217 micrograms per cubic metres, while numeric figures of Gwalior and Allahabad are 176 and 170, respectively.