BEIJING -- China's environmental watchdog vowed on Monday to crack down hard on environmental pollution and severely punish law enforcers who cover up or indulge violators.

A circular issued by the Ministry of Environmental Protection, the National Development and Reform Commission and other concerned central departments, announced that a special campaign running from May to November will mainly deal with irregularities causing air pollution and ground water contamination, areas that have been the top subjects of public complaints.

Surveillance will be enhanced on the coal-burning equipment of electric power plants and steel and cement factories, the circular said, adding that inspections will be stepped up on sewage discharge.

Inspections will also be enhanced in the heavy metal, leather production and electroplate sectors, it added.

According to the circular, pharmaceutical companies will also become a key target to guard against irregular discharges, illegal transfer of sewage water and acts violating rules on disposal of dangerous waste.

Local government officials will be warned if inspection and correction work does not make tangible progress, the circular quoted a senior official of the Ministry of Environmental Protection as saying.

Law enforcers who fail to deal with, cover up, or indulge law breakers will be seriously pursued in accordance with law and disciplines, the unnamed official said.

The watchdog will urge immediate attention be paid to serious air pollution issues or cases that have met with a large volume of protest and have harmful social influence, he added.