Air pollution in Beijing reached hazardous levels on Saturday as smog engulfed large parts of China despite efforts to clean up the foul air. At noon, the U.S. Embassy in Beijing reported the level of the poisonous, tiny articles of PM2.5 at 391 micrograms per cubic meter. The World Health Organization considers the safe level at 25 micrograms per cubic meter of the particulates. The city has been shroud in gray smog since Friday, reducing visibility to a few hundred meters (yards). The Ministry of Environmental Protection has forecast severe pollution for the greater Beijing region, the western part of Shandong province and the northern part of Henan province until Tuesday, when strong winds from the north are expected to blow away air pollutants. The ministry has advised people to stay indoors.