A citizen rides amid dense fog in Zhengzhou, capital of central China's Henan Province, Jan. 11, 2013. A heavy fog hit Zhengzhou on Friday. The visibility is less than 500 meters, and in some areas, it is less than 100 meters. Heavy fog has enveloped Henan Province since Jan. 8 and the situation will continue in the next three days. (Xinhua/Wang Song)
