Seven environmental protection NGOs have appealed for domestic and international fashion brands to set up screening systems to identify polluters in their supply chains, a report said on Wednesday.

The textile industry is said to be a continuing source of water pollution in China, and that dyeing and printing enterprises in this industry are reportedly the major polluters.

Some suspected polluters are suppliers for world-renowned clothing brands such as Polo Ralph Lauren, Uniqlo and Tommy Hilfiger, according to the report, which was issued by the NGOs.

Ma Jun, director of the Institute of Public and Environmental Affairs, one of the seven NGOs, cited official figures showing that at least 400 printing and dyeing enterprises in Zhejiang province have exceeded sewage discharge levels in the first half of this year.

The report said most of the polluting factories are in Zhejiang, Jiangsu, Guangdong and Fujian provinces, which all have coastlines.

It also listed 49 fashion brands with suppliers that have environmental issues.

Joey Lee, project manager at the institute, said, "We suggested that these fashion brands set up a screening mechanism to identify polluters in their supply chains, forcing their suppliers to explain their poor records on pollution and to rectify the situation."

Adidas, H&M and Nike have started to establish a system to identify such suppliers and to recognize the pollution problem facing their dyeing and printing operations.

However, most fashion brands have chosen to ignore the problem, Lee added.

The social media officer at Tommy Hilfiger in China, identified only as Ji, said the company did not know about the issue and declined to give a response. China Daily tried to reach other fashion brands for comment, but the calls went unanswered on Wednesday.

The Ministry of Environmental Protection released new water pollutant discharge standards on Jan 1, tightening the standards for major pollutions.

But so far, only Zhejiang province has implemented the new standards, taken action against polluters and disclosed related figures, the report said.

In the Keqiao district of Shaoxing, which has the largest group of textile factories in Zhejiang, 10 small companies that failed to reduce water pollution were forced to close this year, said Jin Shanfu, chairman of the Shaoxing Textile Industry Association.

Of 238 printing and dyeing companies in the district, 210 have set up sewage pre-processing facilities with a daily processing capacity of 570,000 metric tons, he said.

The district has also established an online surveillance system to monitor sewage emissions.

Jin said: "The government has the power to switch off the valves at every company. Once emissions exceed the required amount, valves will be switched off immediately."

Wang Qian contributed to this story.