Around 12,000 people demonstrated in China's northeastern city of Dalian on Monday
An influential Chinese newspaper on Monday urged citizens against taking their grievances to the streets, after thousands forced the closure of a chemical plant they said could belch out carcinogens.
The warning in The Global Times, an English-language daily with close links to the Communist Party, came a day after around 12,000 people demonstrated in the northeastern city of Dalian following fears of a toxic leak at the factory.
Local authorities acted unusually swiftly, promising the "immediate" shutdown of the plant -- owned by China's private Fujia Group -- and pledging to relocate the factory.
But the comment piece in The Global Times warned this was not the right way for Chinese people to express their complaints.
"Some Dalian citizens went to the streets to express their views, however, [this is] a move that should not be advocated in China," said the paper, which is owned by Communist party mouthpiece The People's Daily.
"While the Dalian local government decided to stop and relocate the project, Chinese society has objected to taking their issues to the street," it added.
The Chinese-language media, meanwhile, devoted little space to the protests, while online postings were swiftly removed in a sign of official concern that disaffected people elsewhere could be inspired by the successful demonstration.
"This (the protests) is about direct opposition to the policies of the local government, the kind of thing they don't want to see elsewhere -- it could set an example," said David Bandurski, a researcher at the Hong Kong-based China Media Project.
A search for the word "Dalian" on Sina's popular Twitter-like Weibo service yielded a message saying the "search results cannot be displayed due to relevant laws, regulations and policies".
Authorities frequently censor any online content they deem sensitive and a threat to the ruling Communist Party, in a huge system dubbed the Great Firewall of China.
Bandurski said photos of the protest, which appeared on Weibo before being deleted by censors and re-posted by online users, suggested the agitation was well-coordinated as many of the young protesters wore identical t-shirts.
"We're talking about mostly young, middle-class citizens, and they must have used social media and mobile networks to organise this," he said.
The largely peaceful protest in the port city was the latest bout of unrest to hit China as anger over issues such as social inequality and environmental degradation boils over.
Internet users on Weibo posted photos of another mass protest that took place on Sunday in the southwestern city of Chengdu, which they said involved 5,000 people complaining about electricity supply issues.
An official at the municipal government, who refused to be named, told AFP "hundreds" of people had gathered on the streets, but added that the police had maintained order and the incident had been "solved".
In a sign that censors may also be blocking information about that bout of unrest, searches for the word "Chengdu" paired with "protest" on Weibo yielded no results.
In its comment piece, the Global Times said such expressions of public opinion had become frequent in China.
"This indicates social progress, as it shows the public has more opportunities to be heard," it said.
However, the newspaper said the demonstration "should not be simply seen as a victory of a protest".
"In fact, in China, reasonable public appeals will eventually be accepted by the government" it said.
Pollution-related scares are common in China -- the world's biggest emitter of greenhouse gases -- where an emphasis on economic growth over the past three decades has led to widespread environmental degradation.
As such, environmental problems have triggered a rising number of riots and other forms of public unrest over the years.
In one high-profile case in 2007, work on a billion-dollar petrochemical plant in the southeastern port city of Xiamen was scrapped following huge public discontent about industrial pollution.