Authorities in eastern China have suspended construction at a petrochemical complex after days of protests by residents who fear that it will pollute the region.

Municipal officials in Ningbo city said Sunday a planned expansion of the complex is on hold pending a “scientific review” of its environmental impact. The petrochemical facility in Ningbo's coastal Zhenhai district is owned by a subsidiary of Sinopec, a major Chinese oil refiner.

Witnesses said thousands of Ningbo residents joined street protests against the project in the days leading to Sunday's climb down by the local government. Activists said riot police fired tear gas to disperse the crowds, while authorities said some protesters overturned vehicles and assaulted officers.

Officials said Ningbo's mayor and its Communist Party chief met with residents Saturday night to listen to their complaints about the petrochemical complex. It is not clear if the municipal government will ultimately cancel the project or revive it when public pressure dissipates.

Activists said hundreds of residents gathered outside a Zhenhai government building Sunday and marched through nearby streets to keep the pressure on the authorities. They said police allowed the march to proceed.

China's Communist rulers have been trying to keep the country stable ahead of a once-in-a-decade leadership transition next month.

China has seen a series of environmental protests this year, with residents venting their anger about the health risks of industrial projects approved by local governments. Earlier this month, residents demonstrated against the building of a coal-fired power plant on the southern island of Hainan.