A men wearing the mask rides a bicycle on the street during severe pollution on January 29, 2013 in Beijing, China. The 4th dense fog envelops Beijing with pollution at hazardous levels in January.
{"Image ImageDescription": "BEIJING, CHINA - JANUARY 29:  A men wearing the mask rides a bicycle on the street during severe pollution 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)", "Image Copyright": "2013 Getty Images"}