SHIJIAZHUANG - The environment in parts of North China's Hebei province has deteriorated sharply, a central inspection team said on Tuesday.

Four rivers, including the Canglangqu, Shibei River, Liaojiawa River and Cha River, are heavily polluted within Cangzhou city, with average pollutant concentrations in the four up 30 percent in 2015 from 2013 figures, inspectors noted.

A series of illegal projects were discovered, including construction of villas near the province's protected drinking water sources.

Inspectors attributed the environmental violations to ineffective supervision by local regulators.

"Former leaders of the provincial Communist Party of China committee didn't take environmental protection seriously and failed to make changes from 2013 until July 2015," said the team.

During the inspection, 200 enterprises were shut down, 123 people were arrested and another 366 were held accountable.

The inspectors, who were sent to Hebei from Dec 31, 2015 to Feb 4, ordered local authorities to submit rectification measures to the State Council within 30 work days.