Local officials promised Sunday to suspend construction of a massive waste incinerator in eastern China after a violent demonstration by residents fearful of pollution left dozens injured.

The rally was the latest in an increasing number of angry protests over environmental concerns in the country, where three decades of rapid and unfettered industrial expansion have taken a heavy toll.

"Residents will be invited to give their opinion before the project is officially launched," the Yuhang district government in the city of Hangzhou said in a statement.

"The construction of the incinerator will stop... if we do not have the support of the population," it added.

Protesters clashed with hundreds of police at a rally in the city on Saturday, leaving at least 10 demonstrators and 29 policemen injured, state media reported.

More than 30 cars were overturned during the confrontation, with residents setting fire to two police vehicles and smashing up another four, the official Xinhua news agency said.

Plans for the waste complex were made public in April and local residents fear pollution from the plant could negatively impact their health.

On Sunday the Yuhang government's promise was met with scepticism by protesters, who said they had little faith it would do anything more than delay the inevitable.

"We don't believe them. Our protest caught the attention of the central government, so they're under pressure at the local level to deal with the controversy fast to avoid punishment," a protester named Li told AFP.

The activist, who did not give his full name, said many of his fellow demonstrators had been beaten by police, but added he had not heard of any deaths.

Regardless, he vowed to pursue his opposition to the incinerator. "If the government resumes the project, we will continue to confront them," he said.

Hangzhou, built around the picturesque West Lake, is a major draw for tourists in China. But the city of nine million has seen its popularity decline in recent years due to air pollution, which also plagues the capital Beijing and other cities.

Last month state media reported that police detained 18 people over large rallies opposing a chemical plant in Maoming in the southern province of Guangdong after thousands of demonstrators took to the streets for days of protests.

Local authorities in the coastal city of Xiamen cancelled plans for a plant producing paraxylene, a chemical used to make fabrics, after thousands took part in a protest in 2007.

And a huge demonstration in the northeastern city of Dalian in 2011 prompted authorities to announce the closure of another factory, although it was apparently still operating two years later.