BEIJING -- A report released by China's environmental authority on Friday estimated that a total of 280 million residents in China are using unsafe drinking water.

The report, issued by the Ministry of Environmental Protection, was based on a sampling survey of 91,527 permanent residents aged 18 and above in 31 Chinese provincial-level regions to evaluate Chinese people's exposure to environmental risks.

The survey also found that a total of 110 million Chinese people are living less than 1 km away from at least one industrial site with pollution concerns, such as petrochemical, coking or thermal power plants.

Moreover, about 140 million people live within 50 meters of a main communication artery, it said.

The report urged establishing a network for monitoring environmental health risks in the country's high-risk areas and intensifying risk evaluation measures and warnings.

The survey was conducted between 2011 and 2012.