Motorcars run amid heavy fog in Pingxian County, north China's Hebei Province, Feb. 22, 2013. Some parts of Hebei Province were hit by fog and smog on Feb. 22 morning and the provincial meteorological bureau has issued a red alert. (Xinhua/Wang Xiao) 

A citizen rides a bicycle amid heavy fog in Pingxian County, north China's Hebei Province, Feb. 22, 2013. Some parts of Hebei Province were hit by fog and smog on Feb. 22 morning and the provincial meteorological bureau has issued a red alert. (Xinhua/Wang Xiao) 

A citizen walks amid heavy fog in Pingxian County, north China's Hebei Province, Feb. 22, 2013. Some parts of Hebei Province were hit by fog and smog on Feb. 22 morning and the provincial meteorological bureau has issued a red alert. (Xinhua/Wang Xiao)