China has banned or restricted certain chemicals that have been identified as persistent organic pollutants in order to fulfill its international obligations, according to the Ministry of Ecology and Environment.

According to a notice on the ministry's website, China in March banned most uses of perfluorooctane sulfonic acid, or PFOS, which is used to protect fabrics from stains, among other things.

Its use will continue in some manufacturing sectors, as allowed under the Stockholm Convention, an international treaty on pollutants that China formally joined in 2004 - for example, in photo imaging, semiconductors, aviation hydraulic fluids, fire-extinguisher foam and some medical devices.

Huang Jun, associate professor of environmental chemistry from Tsinghua University, said the United States phased out production of PFOS in the early 2000s after researchers found evidence that indicates the chemical is a hazardous pollutant.

"So a market opportunity was opened up for other countries like China," Huang said. "Since the industry has just started to boom in China, it is not an easy decision for China to restrict the production of PFOS. However, the government and green associations are moving forward with the restriction and seeking substitutes. Despite challenges, efforts will continue to protect the environment."

"Applications like this are about life and safety, which should be the top priority," he said.

The pesticides lindane and endosulfan were banned along with PFOS, the notice said. The two chemicals, used as insecticides for vegetables, trees, fruits and soil treatment, were listed as persistent organic pollutants by the Stockholm Convention. They are persistent and accumulate easily in the food chain.

The production and agricultural use of lindane was banned in 2009, and in 2012 a global ban on endosulfan took effect.

Huang said alternatives to the two include not only nonpolluting chemical substitutes that can be used without major changes in process design but also changes in agricultural processes such as using black lamps and sticky boards to trap insects.

Any breach of the ban will be subject to severe punishment, the ministry said. It issued the notice with 10 other government departments, including the Ministry of Agriculture and Rural Affairs, the Ministry of Commerce and the General Administration of Customs.

Yu Fawen, researcher with the rural development institute with Chinese Academy of Social Sciences, said joint actions should be taken by local authorities, farmers and business to eliminate the pesticides that pose threats to soil and underground water quality.

"It is urgent to ban the use and production of these chemicals, because they will eventually damage the health of humans," he said.

To further implement the convention, China plans to restrict certain flame retardants, by the end of 2021, according to a guideline unveiled by the central government in 2017.