China will strengthen supervision of the government's air pollution control efforts and require the timely release of city assessment data, according to the second draft of new regulations.

Only 16 of the country's 161 major cities reached the national standards on air quality last year, statistics from the Ministry of Environmental Protection show.

The standards require cities to improve assessments of their performance on air pollution and strengthen the role of assessments in achieving short-term pollution abatement goals, according to a report by the legal committee of the National People's Congress, the top legislative body.

The draft amendment to the Air Pollution Law, sent to the NPC Standing Committee for a second reading on Wednesday, said the central government will conduct assessments of provincial level governments and those bodies, in turn, will assess their cities and release the results to the public in a timely manner, said Sun Baoshu, deputy head of the committee.

City governments must annually report their results in reaching their short-term goals to the local people's congress, an extra step from previous years, the second draft noted.

The ministry suspended five cities that failed the environmental assessment process, the first step required for governments to launch projects, after they didn't reach their goals last year, said Chen Jining, minister of environmental protection.

As the leading regulation to curb air pollution, the Law on Air Pollution Control and Prevention contains comprehensive measures targeting various sources of contaminants.

Exhaust from vessels and vehicles face tougher restrictions in the draft, and ships and vessels will be required to use standard diesel fuel in an effort to cut emissions.

China is home to eight of the world's 10 largest ports in terms of cargo handling capacity, and they contribute significantly to pollution in coastal regions, said Xiong Yuehui, head of scientific standards on emissions at the ministry.

In 2013, more than 8 percent of the national sulfur dioxide emissions and more than 11 percent of nitrogen oxide emissions, both major airborne pollutants, were from vessels' exhaust, he said.

According to the draft, vessels at berth should operate on land-based power provided by the ports. Ports, both new and existing, must be equipped with such power facilities, it said.

To cope with the increasing number of vehicles, local governments may impose driving restrictions to lower air pollution, but they must first solicit public opinion, the draft said.

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The China Central Television headquarters building is backed by a shroud of smog in Beijing on Tuesday. Wang Zhuangfei / China Daily