By Don Lee

May 11, 2013, 10:15 p.m.

SHANGHAI -- Reflecting growing social tensions over China's high pollution, hundreds of demonstrators marched here Saturday to protest the building of a lithium-ion battery plant, while officials of another major Chinese city where people took to the streets recently over a chemical refinery said they might pull the project.

The Shanghai protest was the third in recent weeks since residents learned that Hefei Guoxuan High-Tech Power Energy Co. would construct a battery factory in the Songjiang district of this financial hub. Last month, a caravan of cars bearing green ribbons drove around the community to call attention to concerns that the plant would pollute the air and local water sources.

Video footage and photos of the march Saturday showed adults and children holding Chinese flags and signs depicting black smoke and saying, "No factory; we love Songjiang." Reuters news service estimated that the demonstration attracted 1,000 people, who walked peacefully while being watched by police. No arrests were reported.

The protests, plus petition signatures collected from more than 10,000 residents, already have pushed Songjiang officials to scale back the factory's production capacity, according to local media. But neither that nor government statements about the environmental impact have satisfied the community.

The march took place under sunny but hazy skies in what was one of the worst air-pollution days ever recorded, according to a common reading of air quality. Shanghai authorities issued a warning that people should limit their outdoor time.

Environmental concerns have become an increasing source of social unrest in China as residents have become emboldened about voicing their outrage over damage from unbridled industrial growth, sometimes leading to violent clashes with police.

At times, protests have pushed authorities to make concessions. On May 4, hundreds of people took to the streets in the southwestern Chinese city of Kunming, where residents have complained for months about a petrochemical facility planned by China National Petroleum Corp.

On Friday, the city's mayor pledged to cancel the project if most residents objected to it.