Hebei province has suspended dozens of polluting companies that violated environmental protection rules, and will continue inspections in coming months to improve air quality.

This month, Hebei began a half-year campaign to fight smog, imposing 40 tough new measures to cut emissions from sources like burning coal, vehicle exhaust, heavy industry and construction.

The Hebei Environmental Protection Bureau sent out 30 teams and over 1,200 inspectors on Sept 5 to supervise companies and government organs. By Monday, they had inspected 15,021 companies, 16 percent of which had infractions like lacking proper equipment or unauthorized discharges of waste.

Sixty-six firms were temporarily suspended, two permanently shut for illegal operations, one had further production restricted and 640 were fined a total of 77 million yuan ($11.6 million).

Most are large companies in major industries, including iron and steel, coking, glass and construction, said Ren Liqiang, a deputy head inspector at the bureau.

"We didn't expect big firms would still take chances to escape regulations," said Ren, adding that some found ways to operate without controlling their discharges.

Hebei Jingye Group, one of the province's big iron and steel companies, with assets of 27.2 billion yuan, was found to lack environmental protection facilities and to have tampered with instruments for monitoring discharges.

"They will be a focus in the next inspection round," Ren said. The next round starts on Sunday and lasts for 25 days.

"If they still don't obey the environmental rules, their executives will be turned over to public security departments for criminal punishment by law," Ren said.