Beijing plans to establish an environmental police force by the end of March, amid tightened controls on air pollution, the Beijing Municipal Environmental Protection Bureau said after the capital and other northern cities are engulfed by a new bout of smog.

The smog descended on Jan 15 across northern and central regions, including Beijing and Tianjin as well as the provinces of Hebei, Shandong and Henan, with the pollution due to worsen, reaching hazardous levels on Jan 17 and Jan 18, according to Li Jianjun, director of the environmental pre-warning department at China National Environmental Monitoring Center.

The smog will begin to disperse on Jan 19 as winds arrive, Li added.

Beijing issued a yellow alert effective on Jan 16, while 14 other cities, including Shijiazhuang in Hebei province, issued red alerts based on a statement by the Ministry of Environmental Protection.

In order to reduce air pollution, the capital has set an ambitious target of cutting average PM2.5 concentration levels to 60 micrograms per cubic meter, a 17 percent reduction compared with the average level in 2016, which was 73.

The term PM2.5 refers to fine particulate matter with a diameter of 2.5 micrometers or less that is hazardous to health.

In addition to strong measures to cut emissions of pollutants, the capital’s planned environmental police force will focus on reducing environmental crimes.

“By the end of the first quarter, the new police team will be set up,” said Fang Li, head of the bureau, adding that the new team will be a branch of the public security police.

“The police’s compulsory measures, including detention, will deter polluters, while cooperation between environmental and public security departments will improve efficiency in dealing with environmental pollution cases,” Fang said.

Guan Ping, chief scientist at Peking University’s Institute of Oil and Gas, said the environmental police force is needed as a matter of urgency to deal with violations effectively.

Guan said that research into environmental pollution uncovered the illegal trade of low-quality coal between shops and households.

“Without law enforcement, such violations are hard to stop,” he said, adding that the environmental police force should possess professional knowledge to make law enforcement more efficient.

Many provinces, such as Hebei and Guangdong, have already set up environmental police forces to strengthen the implementation of laws and regulations on environmental pollution.