China's National Meteorological Centre (NMC) on Saturday issued a yellow alert for heavy fog in the northern and central regions.
Hebei, Henan, Shandong, and Hubei provinces will see heavy fog from Saturday evening to Sunday, with visibility of less than one km in some areas, the NMC said.
South Hebei and north Henan will experience visibility of less than 500 metres, in some areas only 200 metres, Xinhua news agency reported.
China's meteorological alerts are categorised as blue, yellow, orange and red as the severity ascends.
