Authorities in Maoming city on the southern coast of Guangdong province have held a press conference on the protests over controversial plans for a local chemical plant. Police say they have punished 44 people and detained 18 others for violence during the three days of protests.

On Sunday, more than 1,000 people demonstrated in front of Maoming’s government building. Protesters smashed office windows and billboards in a display of anger over plans to produce PX, a petrochemical substance used in plastic.

On Monday the government announced it would to consult the public before going ahead with the facility, but protests continued into a third day. There were even protests in the provincial capital, Guangzhou on Tuesday.

Since 2007, PX projects have been cancelled in Xiamen, Dalian, Ningbo and Kunming after residents protested. It is not yet clear if the Maoming government will follow suit.