China on Tuesday ordered local governments to reduce emissions of "major pollutants" by as much as 10 percent by 2015, amid growing public anxiety over the country's bad air.

Authorities will also start to monitor the smallest and most dangerous airborne pollution, known as PM2.5, in densely populated areas such as Beijing and Tianjin, the government said in a statement on its environmental targets.

"Total emissions of major pollutants should be reduced significantly by 2015," the State Council, or cabinet, said, listing a number of pollutants including sulphur dioxide, but not carbon.

"Urban and rural drinking water supply and environmental security should be protected effectively, water quality should be improved greatly and heavy metal pollution should be controlled effectively."

China also vowed to "significantly" improve safety measures for nuclear energy production and speed up the elimination of "old automobiles and motorcycles" registered before 2005.

The announcement comes amid growing public debate over pollution in China, where more than 30 years of rapid economic growth has left the country's air, soil and waterways severely contaminated.

Millions of Chinese went online to vent their anger after thick smog blanketed Beijing earlier this month, raising health fears and causing hundreds of flights to be cancelled.

Public angst in the Chinese capital over heavy pollution has been compounded by official data showing air quality is good, or only slightly polluted, when smog is visible and figures published by the US embassy rank it as "very unhealthy".

Chinese authorities currently use a method known as PM10, focusing on larger particles in the air.

But the environment ministry has proposed adopting the system favoured by the US embassy, which measures PM2.5.

Protests over environmental pollution are also increasing. In the latest incident, residents in the southern town of Haimen stormed government buildings on Tuesday to protest against a power plant they say is damaging their health.