"They are directly led by SEPA and will not take instructions from local environmental protection departments," Xinhua quoted an unnamed SEPA official as saying.

China has been trying to curb pollution and tighten its monitoring of potential environmental hazards, following major disasters including a toxic spill last year that poisoned the Songhua River, a source of drinking water for millions.

But despite tighter rules and more spending, the government has conceded to being stymied by local officials who are reluctant to use cleaner technologies if they are more expensive and who value economic growth above environmental safety.