A pedestrian walks across a bridge above a main road on a day with high air pollution in Beijing

 
A pedestrian walks across a bridge above a main road on a day with high air pollution in Beijing
A pedestrian walks across a bridge above a main road on a day with high air pollution in Beijing June 6, 2012. A senior Chinese official demanded on Tuesday that foreign embassies stop issuing air pollution readings, saying it was against the law and diplomatic conventions, in pointed criticism of a closely watched U.S. embassy index. The level of air pollution in China's heaving capital varies, depending on the wind, but a cocktail of smokestack emissions, vehicle exhaust, dust and aerosols often blankets the city in a pungent, beige shroud for days on end. REUTERS/David Gray (CHINA - Tags: ENVIRONMENT SOCIETY POLITICS)