Some areas in northern China including capital Beijing are likely to see another day of smog as the national observatory issued an orange alert for air pollution on 4 December.
Heavy smog will stay in some parts of Beijing, Tianjin, Hebei, Shandong, Henan and Shanxi from this morning to tomorrow morning, according to the National Meteorological Center (NMC).
Earlier, Beijing witnessed an orange alert for three days starting 1 December midnight, cancelling outdoor activities in schools and construction projects in the smog-hit city.
Central and southern Hebei will see PM2.5 density higher than 500 micrograms per cubic meter in air with visibility reduced to less than 200 meters, said the NMC.
The NMC said a cold front will help disperse the smog later tomorrow.
China has a four-tier colour-coded system for severe weather, with red being the most serious, followed by orange, yellow and blue.
An orange alert means heavy pollution - PM2.5 density of higher than 150 micrograms per cubic meter of air.
After experiencing frequent bouts of smog, the Chinese public has become increasingly sensitive to the health hazard. To address public concerns, the government aims to cut the density of inhalable particulate matter by at least 10 per cent in major cities by 2017, state run Xinhua news agency reported today.
The NMC also issued an alert for heavy fog in parts of Beijing, Tianjin, Hebei, Sichuan, Chongqing and Guizhou with visibility possibly reaching less than 200 meter.