A Chinese city has released 21 people who were detained after a clash between police and residents protesting against a metals plant they feared would poison them, city officials said.

The release on Wednesday is the second unusual official concession in two days, after the government took the uncommon step of halting the metals project planned by Shanghai-listed Sichuan Hongda.

The city initially had said it would only suspend the project.

 

Thousands of people in the southwestern city of Shifang took to the streets over the past three days against the government's plans to allow the building of a copper alloy plant, the latest unrest spurred by environmental concerns in the world's second-largest economy.

The Shifang government said police had "forcibly taken away 27 suspected criminals" on Monday and Tuesday for tearing down the door of the municipal government building, smashing windows, and throwing bricks and stones at police and government workers.