BEIJING - MAY 9: Traffic jam and smog in Beijing's Central Business District on May 9, 2012 in Beijing, China.Beijing is expected to pass the six million vehicles on its roads by the end of the year.
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BEIJING - MAY 9: Traffic jam and smog in Beijing's Central Business District on May 9, 2012 in Beijing, China.Beijing is expected to pass the six million vehicles on its roads by the end of the year.