In addition to promoting green vehicles, the government has come up with other measures to combat air pollution.

The transport authorities will only allow license plates ending in even or odd numbers to be on roads on alternating days when there is a red alert on air quality, according to a trial emergency plan for severe air pollution the city released in late October.

The plan also prohibits another 30 percent of vehicles for official use from starting their engines on the basis of the even-odd license plate rule.

The rule was introduced in 2007 when the city prepared for the Olympics in 2008. Neighboring Tianjin and Hebei province have also introduced similar measures.

Though it is seen as an emergency measure, experts said it has helped alleviate air pollution in Beijing.

It could help cut 15 percent of the city's PM 2.5 pollutants, Fang Li, deputy chief of the Beijing Bureau of Environmental Protection, told People's Daily.

Li Kunsheng, an official in charge of vehicle emission at the bureau, admits the rule is the last choice in an interview with People's Daily.

If there is a red alert, any measure that can cut the source of pollutants should be put in place, Li said.