China Enveloped In Thick Smog

HANGZHOU, CHINA - FEBRUARY 23: A smog is cast over a bridge in a tourist area on February 23, 2014 in Hangzhou, Smog will continue to blanket China's north and central regions as the the National Meteorological Center (NMC) issues a yellow alert for air pollution. On Friday, PM 2.5 readings in these regions kept rising and exceeded 200 micrograms per cubic meter, far above the 25 micrograms level considered safe by the World Health Organization. (Photo by Lam Yik Fei/Getty Images)