Beijing has issued its second red alert for air pollution this month as a new bout of smog is forecast to hit the capital from Saturday to Tuesday.

The red alert, the most serious level, will last from 7 a.m. Saturday to 12 p.m. Tuesday, limiting vehicles on roads according to odd-even license plate numbers and banning fireworks and outdoor barbecue, the Beijing municipal heavy pollution emergency response headquarters said on Friday.

Parts of north China will see the worst smog so far this year from Saturday, the National Meteorological Center said on Thursday.

The air pollution will be worse than the spell between Dec. 6 and 9, it forecast.

Visibility in Beijing and some neighboring regions will be reduced to less than one kilometer. The density of PM2.5, particulate matter smaller than 2.5 micrometers used to measure air quality, in some of the regions will exceed 500 micrograms per cubic meter. The World Health Organization's recommended maximum is 25 micrograms per cubic meter. 

Citizens are advised to reduce outdoor activities and kindergartens, primary and middle schools are expected to suspend classes during the alert. 

Beijing issued its first ever red alert for air pollution on Dec. 7 after the worst period of air pollution this year when PM 2.5 reached the top of the scale at 500.

(Xinhua)