More than 2,000 people in southern China have unfurled banners in a demonstration against plans for a petroleum refinery.
The gathering in central Kunming - the second one in the city this month - was largely peaceful, though there were minor scuffles with police. Witnesses said at least two people were briefly detained, though it was noteworthy that authorities - made no effort to shut down the rally. A city vice mayor, He Bo, even tried to meet the demonstrators, but his attempts to explain the refinery project to the crowd were cut short by the cries of a protester.
Kunming officials said earlier that the refinery planned by powerful state company PetroChina Co will meet environment standards and is crucial for the local economy, but residents are worried about the air and water pollution that will result.
"We don't need speedy development. What we need is a healthy and peaceful country," Kunming resident Liu Yuncheng said. "I still haven't given birth to a baby. I want to be pregnant and I want a healthy baby."
But while police allowed the protest to proceed, censors scrubbed posts in China's social media that were critical of the project planned by the powerful state Petro China Co, and employees of state companies were asked to promise not to participate in any rally or talk about the project in public venues or online.
The scene in Kunming was in contrast to a planned protest against a petrochemical plant earlier this month in the city of Chengdu , where authorities thwarted the gathering by flooding the streets with police in a supposed earthquake drill, reflecting the balancing act of Chinese officials as they seek to promote economic growth while maintaining social stability.
Members of China's public, especially among the rising middle class, have become increasingly outspoken against environmentally risky factories, in reaction to a decade of development-at-all-costs policies that have polluted the country's air and waterways.
However, they have virtually no say on industrial projects, and have instead turned to organising protests. Several of those turned violent last year, in some cases prompting local governments to scrap plans for factories.
In response to a May 4 protest by Kunming residents, local government officials and PetroChina held a series of public meetings and promised that operations at the 20 billion yuan (£2 billion) refinery would be environmentally clean. The facility is expected to produce up to 10 million tons of refined oil annually. But officials also said the project's environmental evaluation report remains confidential, aggravating a public already upset with a lack of information about the project. Residents remain skeptical about any government claim that the project will be safe.
"We cherish blue skies and white clouds, as well as good air. If you want to build a refinery with 10 million tons of capacity here in the place where we live, we resolutely oppose it," said a Kunming resident who identified herself only by her surname, Liu. "We want a good life. We women want to be beautiful."