Beijing - Hundreds of people took to the streets of the southwestern Chinese city of Kunming on Thursday to protest against the planned production of a chemical at a refinery, the second demonstration this month against the project.
China's increasingly affluent urban population has begun to object to a model of growth at all costs, which has fuelled the economy for three decades, with the environment emerging as a focus of concern and protests.
Photographs on Weibo, China's version of Twitter, showed a crowd of protesters in the centre of the city carrying banners protesting against production at the planned plant of paraxylene (PX), a chemical used in making fabrics and plastic bottles.
"To hell with the refinery, get PX out of Kunming," read the message on one of the banners, seen in a picture posted on Weibo.
"Be open with the environmental impact assessment, oppose pollution," read another banner.
Other pictures from Kunming, capital of Yunnan province, showed a heavy police presence. At least some of the demonstrators appeared to have been detained by the police.
An official who picked up the telephone at the Kunming Public Security Bureau said he was "unaware" of the situation.
Calls to the city government went unanswered.
There were no reports of violence, though some pictures on Weibo appeared to show police struggling to hold back protesters at one point.
Last November, the eastern city of Ningbo suspended a petrochemical project after days of street protests. The year before, big protests against a PX plant in the northeastern city of Dalian forced the city government to suspend it.
More recently, heavy pollution that has blanketed the capital, Beijing, and other cities, as well as scandals over food, have added to the sense of unease.
China National Petroleum Corporation, the country's largest oil and gas producer and supplier, announced in February that the National Development and Reform Commission (NDRC) had approved the refinery project at Anning, just outside Kunming.
The refinery would produce gasoline, diesel, other various chemicals and fertilisers as well as PX, the company said in its submission to the NDRC.
State media last week quoted company officials as saying that the refinery would not produce PX.
Kunming's mayor, Li Wenrong, said that the government would listen to public opinion and call off the whole refinery project if "most of our citizens say no to it", the official Xinhua news agency said.