KUNMING - Seven people were sentenced on Monday in Southwest China's Yunnan province after they were convicted of polluting a local waterway, which was mocked as "milk river" in April, a court confirmed on Tuesday.

Eight people, including the legal representatives and major managers of three ore dressing or mining companies, were convicted of polluting the environment in a court in Xundian county, according to the Intermediate People's Court of Kunming City, capital of Yunnan province.

Two of the eight were fined and sentenced to jail terms of one year and three months and eight months, respectively, while five were also fined and received suspended jail sentences ranging from eight months to one year and two months.

One person who was a minor offender and showed repentance was exempted from criminal penalties, the court said.

The three ore dressing or mining companies must pay fines of 500,000 yuan ($82,065) to 750,000 yuan as they were found to have dumped wastewater into the waterway directly or via hidden pipes from 2010 to March 2013, according to the court.

Media reports in April said that pollution caused the water in a 25-km-long waterway located in Dongchuan District in Kunming to turn milky white, and photos of the pollution triggered public anger.

The local procuratorate later discovered that the major pollutant was toxic xanthogenate. Wastewater discharge, which contained toxic substances and suspended solids, has polluted the water and soil, it said.

A local official said the waterway was not a source for drinking water, but for farmland irrigation.

The country's supreme court and procuratorate jointly issued a new judicial explanation in June imposing harsher punishments on polluters. In the most serious cases, the death penalty could be handed down.