Pollution has turned part of a major river system in central China red and bubbly, forcing authorities to cut water supplies to 200,000 people and close schools, a government news agency reported Wednesday.

Some communities along tributaries of the Hanjiang River — a branch of the Yangtze — in Hubei province were using emergency water sources, while at least 60,000 people were relying on bottled water and limited underground sources, Xinhua News Agency said.

Five schools were closed in Xingou township, while others could not provide food to students, the report said without elaborating.

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Gao Qijin, head of the water company in Xingou township, said officials discovered the Dongjing River — one of the tributaries — was red and bubbly Sunday. The company immediately stopped drawing water from the river, Xinhua cited Gao as saying.

Tests showed the polluted waters contained elevated levels of ammonia, nitrogen, and permanganate, a chemical used in metal cleaning, tanning and bleaching, Xinhua said.

The source of the pollution had not been determined, and an investigation was ongoing.

Local officials closed a gate linking the Hanjiang River to the tributaries, and were using water from the nearby Changhu Lake to flush out the pollutants, the report said.

A paper mill dumped waste water directly into the Hanjiang last September, forcing authorities to cut water supplies for a week in some areas, Xinhua said. It did not say how many people were affected.