Beijing has announced new measures to cut vehicle emissions aimed at curbing pollution.

China's capital city has grappled with severe levels of pollution particularly since January, when Beijing's air quality index regularly exceeded 500, the scale's maximum reading.

Car emissions are believed to account for one-third of PM2.5 -- a major air pollutant, which refers to dangerous airborne particles measuring 2.5 microns in diameter -- in most congested areas in Beijing.

A notice on the Beijing government's website Monday said the city is considering imposing a congestion fee for cars. "Whoever pollutes the air is responsible to clean it up," state-run China Daily on Tuesday quoted Fang Li, spokesman for the Beijing Environmental Protection Bureau, as saying. The government did not indicate how the fees would be imposed or paid.

Beijing currently restricts private cars one workday a week, according to the last digit of the license plate.

"Despite the license plate restriction, the number of vehicles in the city is still overwhelming and contributes substantially to the city's pollution. It's time the city comes up with a stricter regulation," said Yu Jianhua, who heads up air pollution management at the bureau.

The proposed stricter regulation, which would prohibit certain vehicles from seriously congested areas, is expected to further reduce vehicles on the roads.

Details of the plan are still being worked out, Yu said, noting that the government will look at similar initiatives in Milan, Paris, London and Tokyo as a model for Beijing's plan.

"Many cities worldwide have come up with congestion charges, and most of them prove effective," he said.

The Beijing government also aims to keep less than 6 million vehicles licensed by the end of 2017, from the approximate 5.35 million that are licensed now.

Beijing aims to reduce PM2.5 concentration to 60 micrograms per cubic meter by the end of 2017, down 25 percent from 2012.

The World Health Organization recommends particulate levels be kept to less than 25 micrograms per cubic meter. In January, Beijing air quality levels reached nearly 900 micrograms.

Separately, Chinese Vice-Premier Zhang Gaoli, during an inspection tour Tuesday in Beijing to address air pollution prevention and treatment, said the city should cut carbon emissions by opting for high-quality coal for electricity and to choose natural gas for winter heating.

China still relies on coal for about 70 percent of its energy needs.

Noting that the air quality in Beijing has fallen beyond people's expectations, "the strengthening of treatment efforts can no longer wait," Zhang said.