The World Health Organisation has released its list of the world’s most polluted cities, with India’s New Delhi taking the top spot.

The Indian capital city had an annual average of 153 micrograms of small particulates (PM2.5) per cubic metre, causing it to have the dirtiest air in the world.

The 2014 report of the Ambient Air Pollution database contains data from 1600 cities in 91 countries.

Thirteen of the dirtiest 20 cities on the list were in India, with New Delhi, Patna, Gwalior and Raipur taking the top four spots.

Surprisingly, Beijing – once the world’s most polluted city – came in at number 77 based on data from 2010, the most recent WHO could access. According to the report, Beijing’s pollution levels were just over one third of New Delhi’s.

Cleaner cities were those registering PM2.5 readings less than five, including Vancouver in Canada, Hafnarfjordur in Iceland and seven American cities

WHO also revealed that air quality in most cities was actually getting worse.

“Many factors contribute to this increase, including reliance on fossil fuels such as coal fired power plants, dependence on private transport motor vehicles, inefficient use of energy in buildings, and the use of biomass for cooking and heating,” the report stated.