BEIJING, China (Xinhua) – Beijing activated measures for the highest-level air pollution alert yesterday morning, a move the local environmental regulator says will help mitigate pollution.

The Chinese capital issued its second red alert this month on Friday as smog was forecast to hit much of northern China, including Beijing, from yesterday to Tuesday.

Measures, such as limiting vehicles on roads according to odd-even licence plate numbers, and banning fireworks and outdoor barbecues, have been in force since 7:00 am yesterday.

Yet some have questioned the necessity of implementing the measures so early when the air is just slightly polluted.

Wang Bin, head of the emergency response division of the Beijing Municipal Environmental Protection Bureau, said yesterday that measures were enacted in advance to lessen the pollution’s impact and help the public prepare for the upcoming smog, which is forecast to be worse than the previous round this month.

Authorities said the red alert issued earlier this month prevented further deterioration of air quality. Data showed the average discharge of pollutants in the city dropped 30 per cent just 10 hours after red alert measures were put in place.

The National Meteorological Centre said Thursday that parts of north China would have seen worst smog so far this year starting yesterday.

Visibility in Beijing and some neighbouring regions will be reduced to less than one kilometre. The density of PM2.5, particles smaller than 2.5 — micrometers used to measure air quality ­— will exceed 500 micrograms per cubic metre in some regions. The World Health Organization’s recommended maximum is 25 micrograms per cubic metre.

Citizens are advised to reduce outdoor activities, and kindergarten through middle school classes will remain suspended as long as the alert stays active.