Authorities in a Chinese city ordered the immediate shutdown of a chemical plant on Sunday as thousands of protesters took to the streets demanding the factory be moved over pollution fears.The demonstration by some 12,000 residents in the northeastern city of Dalian is the latest bout of unrest to hit China as anger over issues such as social inequalities and environmental degradation boils over. Residents in the port city in Liaoning province gathered in front of the municipal government\'s office on Sunday morning, and were joined by more and more people, the official Xinhua news agency said. Some scuffled with riot police, throwing bottles of water at them as they tried to cordon off one of the city\'s main arteries, but there were no reports of injuries, it added. Hundreds of people then broke off and started moving to other parts of the city, chanting slogans and waving banners. According to unconfirmed postings on Twitter, a lot of armed police vehicles were seen moving into the city. The largely peaceful protest was triggered by mounting fears over the safety of a factory that makes paraxylene -- a flammable carcinogenic liquid used in the production of polyester films and fabrics.On Monday, residents living near the plant had to be evacuated after waves triggered by an incoming storm breached a dyke protecting the factory and threatened to damage the building, sparking fears of a toxic chemical spill. Workers managed to repair the dyke, but residents have been left worried about the potential for environmental damage by the plant, which belongs to the private Fujia Group. The municipal government ordered the plant be closed \"immediately\" after protesters refused to disperse, and also pledged to relocate the plant, Xinhua reported. Calls to the government went unanswered on Sunday. One hotel receptionist, who refused to be named, told AFP by phone that protesters were worried about their health. \"If people had a better choice, they would not take to the streets,\" she said.Pictures of the protest posted on Sina\'s Weibo, the Chinese equivalent of Twitter, showed people marching down a street with a banner that read: \"We want to survive, we want a good environment, give me back my Dalian.\" Other pictures showed wide streets full of protesters, hundreds of people staging a sit-in on a square in front of the government office, and children taking part in the demonstrations with their parents.In a sign of the sensitivity of the protest, China\'s censors appeared to be blocking any mention of the subject on Weibo.Searches for \"Dalian\" came up with a message saying \"search results cannot be displayed due to relevant laws, regulations and policies.\" Pollution-related scares are common in China -- the world\'s biggest emitter of greenhouse gases -- where an emphasis on economic growth over the past three decades has led to widespread environmental degradation. As such, environmental problems have triggered a rising number of riots and other forms of public unrest over the years.In one high-profile case in 2007, work on a billion-dollar petrochemical plant in the southeastern port city of Xiamen was scrapped following huge public discontent about industrial pollution.The Dalian protest is the latest bout of unrest to hit China in recent months, as social discontent and ethnic tensions boil over.On Thursday, thousands of people took to the streets in the southwestern province of Guizhou, with some smashing and burning vehicles, after a city official -- \"chengguan\" in Chinese -- injured a female cyclist.The \"chengguan\" -- responsible for low-level policing on China\'s streets -- are widely disliked and have a reputation for using brute force against civilians. In July, the far-western region of Xinjiang -- home to the mainly Muslim Uighur minority -- was the scene of at least three violent attacks and clashes that killed more than 30 people. And in late May, thousands of ethnic Mongols protested in northern China for several days over the killing of a herder.