China will remove the cap on fines against factories which cause air pollution starting next year, as the nation moves to intensify efforts to improve air quality, according to a latest amendment to the law on preventing and controlling air pollution endorsed by the nation's top legislature on Saturday.

The amendment also states that executives of these factories will be severely fined.

Experts had said that the original fine - up to 500,000 yuan ($78,250) - is too low compared with the millions of yuan the companies earn. 

The government has defined quality air as an index reading of up to 100.

"The new law sets a target on air quality, which is making progress," said Chang Jiwen, vice director of the Research Institute of Resources and Environment Policies of the Development Research Center of the State Council (DRCSC).

Li Zuojun, another environment expert at the DRCSC, added that the first law on combating pollution may help lead to future laws against land and water pollution.

The amendment also removed a provision allowing local governments to restrict or ban the use of vehicles as a way of fighting air pollution, following public discussions over the value of such restrictions.

Hao Ruyu, vice chairman of the National People's Congress' Financial and Economic Committee, said he supports the amendment to protect citizens' property rights, the Xinhua News Agency reported. "People buy cars and pay taxes on them. Banning them from driving on certain days deprives them of the right to use their vehicles," he said.

While China's gasoline roughly follows Europe's standard in terms of sulfur content, the allowable content of olefin, arenes and benzene in diesel is far higher.

Li Mengliang, an expert at the China Automotive Technology and Research Center, said environmental authorities should work with other departments to maintain the standard, Xinhua reported.