Beijing set to exit list of world's top 200 most-polluted cities

China's capital of Beijing is on track to drop out from the list of the world's top 200 most polluted cities this year, with hazardous smog concentrations falling to their lowest on record in Aug. The city has been on the frontline of a war on pollution since 2014. However, the city's air quality in 2019 will still likely be more than 4 times higher than the WHO guideline.