China shut down a solar panel factory on Monday after hundreds of angry residents staged days of violent protests over pollution, the second such incident in as many months.

A large red sign at the entrance to the factory in the eastern city of Haining announced the temporary closure, which came a month after authorities agreed to relocate a chemical plant following protests over pollution fears.

The swift decision to shut the solar panel plant underscores the intensity of official concern over mounting public anger about pollution in China, where an emphasis on economic growth has led to widespread environmental degradation.

"Everyone is angry beyond belief. This couldn't happen in Shanghai," one man living next to the plant told AFP, speaking on condition of anonymity.

"We have been complaining about the pollution for half a year, but it was only when we protested that this got any attention," said another local resident.

The protesters broke into the factory, operated by the US-listed company Jinko Solar, in Zhejiang province, ransacking offices and overturning vehicles before being forced back by police in a three-day protest from Thursday.

State media reports said demonstrators were demanding an explanation for the deaths of large numbers of fish in a nearby river.

On Monday, Haining's city government said tests had shown the factory was emitting excessive levels of fluoride, which can be toxic in high doses, as it announced the temporary shut-down.

"(We) ordered the company to halt production and overhaul the production procedures that involve emission of waste gas and waste water," it said in a statement.

The city government said it had imposed a fine of 470,000 yuan ($73,550) on Jinko Solar, which is listed on the New York Stock Exchange and has more than 10,000 employees working in plants in eastern China.

Jinko apologised for what it said had been a leak. Waste containing fluoride had been stored outside the factory, it said, but polluted a nearby river after heavy rains in late August.

"(The incident) has triggered panic among local people, caused many problems to the local government and inconvenienced the company's employees, and we express our sincere apologies," it said.

Chief financial officer Zhang Longgen said the leak was an accident and that the company would pay damages to residents.

The city government said police had detained a man for spreading "rumours" on the Internet about the number of sufferers of leukaemia and other cancers living near the plant.

Another 20 people were detained on charges of disrupting public order, theft and vandalism, including throwing bricks and stones at police officers, it said.

Chinese authorities have repeatedly voiced concerns about the role of online social networks as citizens increasingly turn to the Internet to vent their anger in a country where authorities maintain a tight grip on the media.

China, which has the world's largest online population with 485 million users, constantly strives to exert its control over the Internet, blocking content it deems politically sensitive as part of a vast censorship system.

But the huge and rising popularity of weibos -- microblogs similar to Twitter that have taken China by storm since they launched two years ago -- has posed a major challenge to the censors.

In July, a high-speed train crash in Zhejiang that killed at least 40 people sparked an outpouring of public fury on social networking sites, where thousands demanded to know why more care had not been taken over safety.

A blogger living near the accident site in the city of Wenzhou is widely believed to have broken the news of the crash, while millions of others kept up a steady barrage of criticism in the days that followed.

Bloggers were also thought to have orchestrated the largely peaceful protest against a chemical plant in the northeastern city of Dalian, although posts and photographs were swiftly removed from the Internet after the demonstration.

Local authorities last month ordered the immediate shut-down of the plant in light of the protests, which drew about 12,000 people at their height and saw scuffles with police.

Related Links
Our Polluted World and Cleaning It Up

Tweet