A major anti-pollution protest has forced the Chinese government to take swift action for the second time in as many months, spurred by a rising environment movement that is spreading online.More than 500 residents living near a plant making solar panels protested for three days last week in the eastern city of Haining, forcing authorities to temporarily shut the factory, which belongs to the US-listed Jinko Solar. The incident came just over a month after authorities in the northeastern city of Dalian agreed to relocate a chemical plant following similar protests, underscoring official concern over mounting public anger about pollution. \"Citizens, particularly a rising Chinese middle class, have become more aware about how deep the impact of environmental issues is to their health,\" said Phelim Kine, senior Asia researcher for New York-based Human Rights Watch. \"They are no longer willing to take it passively.\" Protests against pollution are not new to China, as breakneck economic growth over the past three decades has caused severe degradation of air, land and water quality.But the growth of social networking, in particular Twitter-like \"weibo\" or microblogs, has helped spread the word about environmental issues and mobilise protests against perceived polluters. Wong Yiu-chung, a politics professor at Hong Kong\'s Lingnan University, said the shutdown of plants in Haining and Dalian was directly linked to the rising power of the Internet. \"The government moved quickly to order a halt in production on fears news of the protest would further spread on weibo, given the control on traditional news outlets,\" he told AFP. Zhang Zhi\'an, a communications professor at Zhongshan University in the southern province of Guangdong, agreed, saying microblogs had helped give a voice to people with grievances. \"It has played an important role in gathering public opinion, which has helped some vulnerable groups,\" he said.China, which has the world\'s largest online population with nearly 500 million users, constantly tries to exert control over the Internet by blocking content it deems politically sensitive as part of a vast censorship system. But the rising popularity of weibos has posed a major challenge to the censors. A blogger living near the site of a deadly high-speed train crash in Zhejiang province in July is widely believed to have broken news of the accident, while millions of others kept up criticism in the days that followed.Bloggers were also thought to have orchestrated the largely peaceful, 12,000-strong protest in Dalian, although posts and photographs were swiftly removed from the Internet after the demonstration.Residents near the Jinko Solar plant, meanwhile, said they had voiced concerns about pollution for half a year, to no avail. One elderly man who has lived in the area his whole life told AFP the air smelled bad and locals had no idea whether it was harmful to their health.The issue finally came to a head with the deaths of a large number of fish in a nearby river and an Internet posting blaming the factory for polluting the area, which residents say has since been deleted. Protesters broke into the factory in Zhejiang, ransacking offices and overturning vehicles before being forced back by police in a three-day protest from last Thursday. News of the incident started emerging on blogs and weibo, before being reported by the official Xinhua news agency on Sunday -- a day before authorities decided to temporarily shut the plant.But local residents said this success was bitter-sweet, claiming the government had employed hard tactics to stop the mass protest, as well as trying to appease locals with pledges to stop pollution.They say riot police used force to disperse the protestors, who overturned cars and threw rocks. \"They beat them (the protestors) like dogs,\" one young man, who lives just outside the walls of the Jinko plant, told AFP.Haining\'s city government said Tuesday 31 people had been detained over the protests and another 100 were to be given \"legal re-education\", which normally involves giving minor offenders classes about the nation\'s legal system. It had earlier put that number at 21, including one man held for spreading \"rumours\" online about people living near the plant allegedly suffering from disease, highlighting government concern over the power of the new medium.