Around a third of government vehicles will be taken off the road in Shanghai when the air is heavily polluted, a national lawmaker from the city's environmental protection bureau said yesterday.

Shanghai government is also to scrap more vehicles that do not meet emission standards. [File photo]

Local government bodies will have to stop using around 30 percent of their vehicles on seriously polluted days, or when the Air Quality Index is above 300, under a new regulation to be released soon, said Zhang Quan, the bureau's director.

Plate numbers of the vehicles involved will be published so the measure can be supervised by the environmental authority and the public, Zhang told a preparatory meeting of the annual National People's Congress, which begins today.

"The regulation includes a series of emergency response measures to curb air pollution at hazardous levels and it will come into effect within three months," Zhang told Shanghai Daily.

Some factories will be suspended and construction sites will have to stop work. Some outdoor activities across the city will also be cancelled when the index exceeds 300.

Air quality is "good" when the index is below 100, "moderate" between 150 and 200, and "hazardous" when the index is over 300.

Since the beginning of the year, Shanghai has encountered about 15 days of polluted air when the index was above 100.

On January 16, it surged to 254, a record high since its introduction last November.

The city government is also to scrap more vehicles that do not meet emission standards and has asked local construction sites to take measures to control dust, Zhang said.

There are also plans to upgrade city taxis to control exhaust emissions, he said.

A pollution tax should be levied on factories, Zhang said.