(Reuters) – The government of the southwestern Chinese city of Kunming on Tuesday banned residents from protesting next week against planned chemical production at a refinery, the ban coinciding with the opening of an important trade fair.

An increasingly affluent urban population has begun to object to a China’s policy of growth at all costs, which has fuelled the economy for three decades, with the environment emerging as a focus of concern and protests.

There have already been two large protests in Kunming against the production of paraxylene (PX), a chemical used in making fabrics and plastic bottles, at the planned plant.

Organizers have taken to the internet to call for the next protest on June 6.

The government of Yunnan’s provincial capital is concerned protests could overshadow the opening of the first China-South Asia Expo, which senior Chinese leaders are expected to attend.

In a statement on one of its microblogs, the Kunming government described the June 6-10 expo as “an important task handed to Kunming and Yunnan by the Communist Party and State Council”.

“During the expo, it is banned to use the internet, microblogs, online chatting systems, text messages or similar methods to incite, plan or to attend illegal gatherings, demonstrations or protests to disturb the expo or social order,” the statement said.

“It is forbidden to spread rumors or messages designed to cause terror,” it said, warning that those who violated the rules would be “severely punished”.

Chinese media have said Kunming authorities have begun demanding people show identity cards before buying face masks, in an effort to identify those who may attend future protests.

Last November, the eastern city of Ningbo suspended a petrochemical project after days of street protests. Big protests also forced the suspension of a PX plant in the northeastern city of Dalian the year before.

More recently, heavy pollution that has blanketed cities including the capital, Beijing, and scandals over food have added to the sense of unease.

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