To boost their power to punish polluters, environmental authorities and police will improve their cooperation in combating environmental crimes, a senior official said on Tuesday.

"Officials often face difficulties in handling crimes related to environmental pollution. They take a relatively long time to tackle, and it's hard to get evidence," said Hua Jingfeng, a top official at the Ministry of Public Security.

"Cooperation between the two departments may substantially add to our ability to fight environmental crimes."

According to the ministry, police have completed 247 environmental pollution investigations since June, when the top court and procuratorate issued a judicial interpretation on the conviction and sentencing standards in such cases.

In the previous decade, police investigated a comparable number of cases.

According to Zou Shoumin, director of the Environmental Protection Ministry's environmental supervision bureau, the two ministries will cooperate on three main types of cases: dumping of hazardous waste, discharging more than the allotted quota of pollutants and deterioration of the ecological environment.

A document on the enhanced cooperation between police and environmental authorities was sent to local environmental and police bureaus on Tuesday. It defines the responsibilities of both in dealing with pollution crimes.

The task of environmental protection departments includes collecting, monitoring and validating evidence, such as the type and concentration of pollutants.

Public security departments must use their legal powers to clear any obstacles to enforcing the law and must facilitate the flow of evidence.

The document said a law enforcement mechanism between police and environmental protection departments will be established with liaison officers appointed to jointly target environmental crime.

A regular conference will be held with police, environmental protection authorities, lawmakers and the people's procuratorate at national, provincial, city and county levels to better coordinate curbing environmental pollution, according to the document.

Environmental authorities and police will jointly supervise severe cases of pollution and release information to the public, the document said.

In urgent cases, environmental authorities and police will jointly investigate to avoid destruction of evidence or the escape of suspects.

Among the industries with high pollution levels are iron and steel making, mining, waste treatment plants, paper mills and dye factories.

Training programs will be set up showing police and environmental officers how to spot and respond to environmental crimes, said Ji Gang, deputy director of the bureau of environmental supervision under the Ministry of Environmental Protection.

"With the surge of pollution cases, environmental protection authorities and police must improve their coordination to effectively combat them," said Wang Canfa, an environmental law professor at the China University of Political Science and Law.

He added that although the document may frighten polluters, it is not a regulation and has no power of enforcement.

Wang, who is also an environmental lawyer, said that through the cooperation mechanism, police can help environmental authorities track down polluters by using their power to enter premises, and to stop, search, detain or arrest suspects.

"Meanwhile, environmental authorities can provide professional knowledge in evidence-collection, including how to detect the illegal discharge of waste or pollution," he said.

In recent years, reports of pollution crises are common in the media. Amid rising public concern, the central government has acted on environmental issues.

Since the 18th National Congress of the Communist Party of China wrote the building of an "ecological society" into the CPC Constitution last year, the nation has shown a strong will to tackle the problem.

The judicial interpretation issued in June on criminal environmental pollution gave courts the power to hand down the death penalty in serious pollution cases.