A Chinese man walks through a park under heavy pollution in Beijing

A Chinese man walks through a park under heavy pollution in Beijing

Under dangerous pollution levels in mid-afternoon, a Chinese man walks through a park in downtown Beijing on October 24, 2016. Air quality in most Asian cities that monitor outdoor air pollution fail to meet the World Health Organization's guidelines for safe breathing. American astronaut Scott Kelly, after spending a year in space, has said that the level of pollution in China is shocking. Photo by Stephen Shaver/UPI