After three nights of increasingly heavy rioting, the police were taking no chances on Monday, deploying dozens of busloads of officers before dusk and blocking every road leading to the factory.

But the angry residents in this village 180 miles south of Shanghai had learned their lessons, too, they said, having studied reports of riots in towns near and far that have swept rural China in recent months. Sneaking over mountain paths and wading through rice paddies, they made their way to a pharmaceuticals plant, they said, determined to pursue a showdown over the environmental threat they say it poses.

As many as 15,000 people massed here Sunday night and waged a pitched battle with the authorities, overturning police cars and throwing stones for hours, undeterred by thick clouds of tear gas. Fewer people may have turned out Monday evening under rainy skies, but residents of this factory town in the wealthy Zhejiang Province vow they will keep demonstrating until they have forced the 10-year-old plant to relocate.

"This is the only way to solve problems like ours," said a 22-year-old villager whose house sits less than 100 yards from the smashed gates of the factory, where the police were massed. "If you go to see the mayor or some city official, they just take your money and do nothing."

The riots in Xinchang are a part of a rising tide of discontent in China, with the number of mass protests like these skyrocketing to 74,000 incidents last year from about 10,000 a decade earlier, according to government figures. The details have varied from incident to incident, but the recent protests all share a common foundation of accumulated anger over the failure of China's political system to respond to legitimate grievances and defiance of the local authorities, who are often seen as corrupt.

A sign of the leadership's growing concern over the increasing turbulence can be seen in a proliferation of high-level statements about the demonstrations.

In a nationally televised news conference this month, Li Jingtian, deputy director of the Communist Party's organization bureau, complained that "with regard to our grassroots cadres, some of them are probably less competent, and they are not able to dissipate these conflicts or problems."

In another widely remarked statement, Chen Xiwen, an economics vice minister who oversees agricultural affairs, saluted the Internet's role in allowing the central government authorities to learn of unrest more quickly and praised demonstrating farmers for "knowing how to protect their rights."

The people of Xinchang were reluctant to speak openly about the uprising, since they would be subject to immediate arrest if they were identified. But from conversations with numerous residents, many of whom took part in the protests, it was possible to put together a detailed picture of the events that unfolded.

In Xinchang, as with many of the recent protests, the initial spark involved claims of serious environmental degradation. An explosion at the Jingxin Pharmaceutical Company this month in a vessel containing deadly chemicals reportedly killed one worker, and previous leakages contaminated the water supply for miles downstream, said villagers and one chemical plant worker who was injured in the accident.

Villagers say they appointed a small group of representatives to present demands for compensation, including free health examinations and medical care for people who live near the plants, which produces a strain of antibiotics called quinolones.

When they sent a group on July 4 to demand an audience with factory officials, they say, security guards beat the representatives.

The next day, the villagers returned in larger numbers and managed to grab a security officer, whom they acknowledge beating. In the meantime, as word spread of the beating of the village representatives and of the worker's death in the explosion, villagers raised the stakes, demanding the outright closing of the factory, which they had complained about for years.

"Our fields won't produce grain anymore," said a 46-year-old woman who lives near the plant. "We don't dare to eat food grown from anywhere near here."

Her husband, a former machine operator, said he had to quit working recently because of persistent weakness and nausea. When local officials posted a notice saying they would reopen the plant a few days after the fatal explosion there, he had been one of the first demonstrators to arrive on the scene, charging the gates and bursting into the factory with a small crowd of fellow protesters.