This article by Gary Haq, University of York was originally published on The Conversation. Beijing, London, Mexico City, New Delhi and Paris are among the cities that have drawn attention for their dangerously high air pollution levels in 2016 – but they’re not alone. The World Health Organisation (WHO) has confirmed that 92% of the world’s urban population now live in cities where the air is toxic. In India, a study found that 41 Indian cities of more than a million people faced bad air quality on nearly 60% of the total days monitored. Three cities – Gwalior, Varanasi and Allahabad – didn’t even manage one good air quality day. Over on the African continent, dirty air was identified as the cause of 712,000 premature deaths – that’s more than unsafe water (542,000), childhood malnutrition (275,000) or unsafe sanitation (391,000). In Europe, it was found that around 85% of the urban population are exposed to harmful fine particulate matter (PM2.5) which was responsible for an estimated 467,000 premature deaths in 41 European countries. It’s not all bad news though: 74 major Chinese cities have seen the annual average concentrations of particulate matter, sulphur dioxide and nitrogen dioxide, decrease since 2014 although the Chinese government’s “war on air pollution” has received criticism.