Week-long smog to end on Wednesday night

A policeman directs traffic amid fog and smog on Chang'an Street in Beijing, capital of China, Feb 22, 2014. Many cities maintained alert for air pollution on Feb 25 since the fog and smog choked northern and central China days ago. (Xinhua/Wang Junfeng)

Citizens wearing masks do exercises amid smog in Changchun, capital of northeast China's Jilin province, Feb 25, 2014. Many cities maintained alert for air pollution on Feb 25 since the fog and smog choked northern China days ago. (Xinhua/Lin Hong)

Smog continues to choke much of northern China, with national weather authorities issuing a pollution alert for a sixth straight day.

Dense haze is forecast for Beijing, Tianjin, Hebei province and parts of Shanxi province for Tuesday and much of Wednesday. Experts say the current stable atmospheric conditions are preventing the smog from dispersing.

The smog will last until Wednesday night, when a cold front is expected to clear the skies. Industrial plants have suspended or cut production, construction has been halted, while barbecues have been banned.

According to the Ministry of Environmental Protection, heavy air pollution was monitored on Tuesday in 58 of the 161 cities that have begun using the new standard for air quality monitoring. Of the 58 cities, 23 were severely polluted.