From Carnegie Endowment for International Peace:
Large-scale public disturbances have been on the rise in China for more than a decade. Media reports describe violence, injuries, and even deaths on both sides, linked to brick-throwing, tear gas, Molotov cocktails, rockets, bullets, beatings, burned vehicles, stabbings, and standoffs between hundreds of police and thousands of protestors. Claims by demonstrators and police are often at odds, but all agree that events can turn deadly and that serious injury and loss of property are common. Issues include labor grievances, taxation, land confiscation, and pollution. Corruption worsens common injustices and further inflames citizen anger.
Industrial China no longer pretends to be a workers’ paradise. In southern China in 2005, 100 shoe factory workers smashed vehicles, threw rocks, and injured three police over unpaid wages. Thousands of workers at an electrical factory struck for four days over working conditions and the right to unionize. In western China, 2,000 laid-off workers barricaded a street and demanded severance pay. In 2004, more than a thousand workers in two south China factories struck for higher pay and one rest day per week. Elsewhere, workers took their bosses hostage over unpaid back wages. Two years earlier, in 2002, 80,000 retired workers in northeast China protested unpaid pensions. [Full Text]
See also Chinese Government Responses to Rising Social Unrest by Murray Scot Tanner, The Economic Basis for Social Unrest in China by Albert Keidel, and CRS Report: Social Unrest in China by Thomas Lum.