In a landmark lawsuit, two non-governmental organizations (NGOs) have demanded compensation of 10 million yuan (1.58 million U.S. dollars) from companies which dumped toxic chemicals in southwest China's Yunnan Province.

Tonnes of chromium-contaminated waste?are still waiting for detoxification in Luliang, Yunan Province on May 22, 2012. [Xinhua]

Friends of Nature (FON) and the Chongqing Green Volunteer Association exchanged evidence with the defendant, Luliang Chemical Industry Co. Ltd. and Luliang Peace Technology Co. Ltd. in court on Wednesday.

If the the NGOs win the case, the compensation will be used for environmental rehabilitation in the polluted areas in Qujing city, said Guo Jinghui, a spokeswoman of FON.

Qujing city's environmental protection bureau also joined as plaintiff in the lawsuit, which was filed last September and accepted by the city's Intermediate People's Court in October 2011.

The court has set up a special environmental protection tribunal, but the trial date has not been confirmed, said Guo.

Earlier this month, seven people connected to the dumping received jail terms from Qujing's Qilin District Court after the companies were found to have dumped 5,000 tonnes of chromium-contaminated waste near Chachong Reservoir and on nearby hills from April to June last year.

Rainfall in June washed some of the chemicals into local water supplies, causing the deaths of 77 heads of cattle. No human deaths have been attributed to chromium pollution in the case, but at least 14 local residents have been diagnosed with cancer since 2002 and many suspect their diseases were caused by contaminated drinking water.

Experts believe the civil case will be a landmark in China as it is the country's first public interest litigation (PIL) filed by grass-roots NGOs, following the country's mulling of including PIL in the Civil Procedure Law.

The Standing Committee of the National People's Congress, China's top legislature, read a draft amendment to the Civil Procedure Law for the first and second time last October and this April.

According to the draft, "legally-registered organizations and social groups" are entitled to file lawsuits in cases of environmental pollution and other behavior infringing public interest.

Wang Canfa, a law professor with the China University of Political Science and Law, believes the trial process would have a direct impact on the Civil Procedure Law amendment.

"The case will be a good start for the PIL filing, not by the aggrieved party, in China," Wang said.

Previous efforts of some grass-roots NGOs in China to file PILs ended up being rejected by courts, mainly because they were not the aggrieved party, said Guo of the FON.

She said before the suit in Qujing, the only PIL accepted and won by a group was filed by the All-China Environment Federation, a government-affiliated organization under the Ministry of Environmental Protection.

She speculated that the governmental background of the federation might have prompted the court accepting and ruling in the case.