A spokesman for the Ningbo city government said in a statement carried by the official China News Service that no further work would now be done on the project in the district of Zhenhai pending further “scientific debate”.

Protesters were objecting to the construction of a paraxylene facility at the plant, owned by a subsidiary of the China Petroleum and Chemical Corporation (Sinopec), the country’s biggest oil refiner. They argued that paraxylene, used in the manufacture of polyester, is a carcinogen.

Plans to build a paraxylene plant in the northeastern port of Dalian were also shelved in August last year following public demonstrations.  

The protests, which had been going on for a week, highlight a major challenge for the leadership as it readies for its once-in-a-decade power transition, and which wants to maintain social stability but also show it is listening to the complaints of ordinary people.

The China News Service said the port city’s mayor and Communist Party secretary met on Saturday evening with members of the public to hear objections to the project.

The city’s public security bureau said protesters overturned cars and attacked police on Friday night while reports on Weibo, China’s version of Twitter, reported that police fired tear gas at the protesters.

More than a thousand people protested again on Saturday but were dispersed by hundreds of police.

The protests come just two weeks before the Communist Party holds a congress which opens on Nov. 8 and will unveil a new central leadership.

The expansion of the Zhenhai petrochemical facility included 15 million tonnes of additional crude oil refining capacity and involved a total investment of 55,9 billion yuan ($8,95 billion), the China News Service said.