Smog persisted in north China for a second day on Sunday and the meteorological center renewed its yellow alert.
Beijing, Tianjin, Hebei, Henan, Shandong, Shanxi and Shaanxi will all continue to experience smog from Sunday to Monday morning, according to the National Meteorological Center (NMC).
South Beijing, central and south Hebei Province and north Henan Province will be especially affected, it said.
The public have been warned to take protective measures when engaging in outdoor activities and those that suffer from respiratory diseases are advised to stay indoors, it said.
China has a four-tier color-coded weather warning system, with red representing the most severe weather, followed by orange, yellow and blue.
