Five things we learned from the world’s biggest air pollution database

2) Beijing is not the global capital of smog it once was

Beijing was the city that came to symbolise smog, but it doesn’t even make the list of the world’s 100 most polluted cities anymore. In 2013, it ranked as the 40th worst city for the particulate PM2.5, but four years on it’s in spot 187. In the 62 Chinese cities for which the WHO has data in both 2013 and 2016, levels dropped by an average of 30%.

Much of this is down to China’s national air pollution action plan, which ran from 2012 to 2017. Now the government is preparing a new three year plan that will set out new targets and measures to “win the battle to defend blue skies”, according to the environment minister.

3) Of the world’s 20 most polluted cities, 15 are in India

Soon after China’s air quality started improving, India’s PM2.5 levels overtook China’s and India became the country with the biggest health impacts from PM2.5.

When comparing the latest available data on PM2.5 levels for each city, the northern Indian cities of Gwalior, Kanpur and Faridabad are the worst, with latest reported levels exceeding 170µg/m3 in 2012, 16 times higher than the latest statistics for London.

The good news is that the Indian government recently announced a National Clean Air Plan, strengthening air quality monitoring and requiring the 100 most polluted cities to devise their own action plans. However, the draft plan does not set targets or timelines for reducing air pollution levels. The government is also finally moving to implement emission standards for coal-fired power plants, after years of delay.

The other countries with entries in the list of 20 most polluted cities are Saudi Arabia, Bhutan, Serbia, Cameroon and Egypt.