Beijing schools kept children indoors January 14, 2013, and hospitals saw a spike in respiratory cases following a weekend of excessive pollution in China's smoggy capital.
A teacher leads her students doing body exercise during class break in a classroom on a foggy day in Jinan, Shandong province, January 14, 2013. Heavy fog enveloped a large swathe of east and central China, with the city's residents being advised to stay
Cranes atop a residential building under construction in central Beijing, April 18, 2012.
Buildings and the Guomao Bridge are pictured amid heavy haze and smog in Beijing, October 29, 2011.