BEIJING, CHINA - DECEMBER 17: A general view of smog in Beijing from famous Jingshan Hill. Smog shows repeatedly in Beijing winter as there is no wind blows on December 17, 2015 in Beijing, China. (Photo by Xiao Lu Chu/Getty Images)
BEIJING, CHINA - DECEMBER 17: A general view of smog in Beijing from famous Jingshan Hill. Smog shows repeatedly in Beijing winter as there is no wind blows on December 17, 2015 in Beijing, China. (Photo by Xiao Lu Chu/Getty Images)