Authorities in a protest-hit Chinese city are making people who buy white T-shirts or print or photocopy banners show identity cards and register their real names, state media said Tuesday.

The regulations are aimed at preventing further demonstrations against a planned paraxylene (PX) chemical plant, the Global Times reported, citing residents in Kunming, in the southwestern province of Yunnan.

PX is a toxic petrochemical used to make fabrics and hundreds of people took to the streets earlier this month to protest against the proposed facility.

Some held banners with slogans including "Kunming mothers seeking health for their babies" and "PX get out", photos posted on a major news portal showed.

China sees around 180,000 protests a year on a wide range of issues, including some against chemical plants in what analysts have identified as a rising trend of environmentally-motivated "not in my backyard" demonstrations.

Two printing and photocopying shops in Kunming contacted by AFP said that they were not accepting any work concerning the PX protests even if customers showed identification and provided their real name.

"They do not want anyone to protest," the Global Times quoted a man from a local clothing store and surnamed Zhang as saying, referring to the authorities.

The official Xinhua news agency earlier this month quoted Kunming major Li Wenrong as saying the government would cancel the plant if "most of our citizens" opposed it.

The demonstrations in the city come amid growing environmental concerns in the country, where new leaders including President Xi Jinping have promised to address the situation.