Public opinion is being sought for a regulation to control the rapid rise in the number of vehicles in East China's Zhejiang province, the Shanghai-based Oriental Morning Post reported on Tuesday.

Drafted by the province's environmental protection department, the regulation aims to ease traffic jams and reduce air pollution caused by car exhausts.

"Pollution caused by car exhausts has become a major cause of worsening air quality in urban areas, and an important factor in generating smog in cities," the department was quoted as saying by the newspaper.

Under the regulation, city governments, based on the air quality in their areas, will be able to limit the number of cars and introduce measures to control the rapid rise in numbers of new vehicles.

By the end of 2012, Zhejiang had 13.1 million vehicles on its roads, the sixth largest figure in China. About 1.17 million of them are new cars registered in 2012, the third consecutive year in which the number of new vehicles rose by more than 1 million.

In the downtown areas of Hangzhou, the provincial capital, there are some 960,000 vehicles, and this number is expected to surpass 1 million in the first quarter.

The regulation is expected to be approved and take effect later this year.