China's national environmental watchdog is to set up 11 branches to independently monitor and investigate environmental issues free from local government interference.

The branches to come under direct control of the State Environmental Protection Administration (SEPA) include five environmental supervision centers in the cities of Nanjing to cover east China, Guangzhou (south), Xi'an (northwest), Chengdu (southwest) and Shenyang (northeast).

Another six branches will monitor nuclear and radiation security in Shanghai Municipality, Guangdong Province, Sichuan Province as well as China's north, northeast and northwest areas.

"They are directly led by SEPA and will not take instructions from local environmental protection departments," said an official with the administration.

The government has been planning a nationwide network for enforcement of environmental laws and regulations independent of local governments since the notorious Songhua River pollution incident.

Last November, a spill of nitrobenzene and other chemicals into the Songhua River forced Harbin, the biggest city in the northeast, to stop water supplies to 3.8 million people for five days.

Experts blame the frequent occurrence of environmental accidents on the inefficiency of local environmental departments, which are affiliated to their local governments, and their timidity in exposing pollution scandals involving local cadres.

The five environmental supervision centers will investigate serious pollution cases, help solve cross-regional environmental disputes and supervise law enforcement in national nature reserves, key scenic spots and forest parks.

The other six stations will carry out daily supervision of security and management at both civil and military nuclear facilities, and monitor emergency work in nuclear and radiation accidents, including terrorist attacks.

The 11 branches will be included in SEPA's 24-hour emergency response system.