Photos: Fog or smog? Pollution at dangerous levels in China
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Credit: Getty Images
BEIJING, CHINA - JANUARY 29: Chinese paramilitary police officers march during the flag-raising ceremony with severe pollution at Tiananmen Square on January 29, 2013 in Beijing, China. The 4th dense fog envelops Beijing with pollution at hazardous levels in January. (Photo by Feng Li/Getty Images)
