In its latest effort to reduce greenhouse gas emissions, China has made it compulsory for coal mines that are sources of significant amounts of methane to collect the gas for utilization, the Ministry of Ecology and Environment said.

"The country will have more marsh gas utilized in coal mining as it makes efforts to control greenhouse gas emissions in the sector," it said in a document on enhancing environmental impact assessments for coal mining projects.

Coal mines that are sources of high-intensity marsh gas, which has methane and carbon dioxide as its major components, must install facilities to extract and utilize the gas mixture, it said.

All extracted marsh gas with a methane content of 8 percent or more by volume should be collected for comprehensive utilization, it said.

Methane can be used as a fuel and can also be used in the production of other chemicals.

The document said coal mines should also explore the utilization of marsh gas with methane content of more than 2 percent.

In a news release issued early this month, the ministry said the proportion of marsh gas that is extracted and utilized in China's coal mining sector remains low. Its requirements for marsh gas with different levels of methane content are based on the capabilities of available technologies.

The UN Intergovernmental Panel on Climate Change has estimated that methane is 34 times stronger than carbon dioxide as a greenhouse gas over a 100-year time scale.

The energy sector is the major source of methane emissions in China, according to Xu Huaqing, director-general of the National Center for Climate Change Strategy and International Cooperation.

"Methane is not only a greenhouse gas but also a major form of clean, low-carbon energy," he said. "The full utilization of methane will not only effectively help control greenhouse gas emissions, but will also bring multiple economic, environmental and social benefits."

Aside from greenhouse gas emissions, the document targets other environmental issues in coal mining, including the disposal of waste rock and water.

It demands that coal mines prioritize the use of waste water generated by coal mining to meet their construction and production needs. They will not be allowed to exploit underground water unless they have fully utilized their waste water, it said.

The ministry said China produced 3.85 billion metric tons of coal last year. Efforts to adjust the country's energy structure and address overcapacity have seen the proportion of coal in China's energy consumption mix decline gradually. But its energy reserves remain dominated by coal and its energy structure's heavy reliance on coal has yet to change fundamentally, the ministry said.