Chinese authorities have rejected state media reports which quoted a government study saying more than two million youths die in China each year from health problems related to indoor air pollution.

The China Centre for Disease Control and Prevention posted a notice on its website late Monday saying the reports were wrong, while state press blamed the matter on false figures released by an air filter manufacturer.

"The China CDC has issued no specific figures on indoor air pollution leading to mass deaths," the notice said.

"Our centre is actively investigating the matter."

The China News Service and other state media had reported Monday that 2.2 million youths died each year from illnesses related to indoor pollutants, with nearly half of them under five years of age.

It cited a study it said was released Sunday by the government.

The original reports could not be found on the Internet on Tuesday.

China is one of the world's most polluted countries, with environmental and health concerns often trampled amid an overriding focus on industrial growth.

A 2007 World Bank report said 750,000 Chinese die prematurely each year due to air and water pollution - a figure edited out of final versions of the report, reportedly after China warned it could cause social unrest.