China has held over 4,660 officials accountable for their poor environmental protection work after the latest round of inspections, the Ministry of Environmental Protection (MEP) said Tuesday.

During the last four days, seven inspection teams reported issues found during a third round of inspections, this time in Anhui, Fujian, Guizhou, Hunan, Liaoning, Shanxi and Tianjin.

The number of people found at fault is sure to increase as local authorities look into the issues raised.

More than 31,000 cases were highlighted by the inspection teams and 405 people were detained, according to the MEP.

While some progress has been made since 2013, common issues were found that require more attention.

Illegal projects in nature reserves have harmed ecosystems, and environmental protection work in some cities needs to be improved.

Local governments must report their plans to resolve outstanding issues to the State Council within 30 business days.

A fourth round of inspections covering the last eight provincial-level areas will begin soon.

China is fighting pollution and environmental degradation after decades of growth left the country with problems such as smog and contaminated soil.

Last year, inspectors looked into 33,000 cases and imposed fines totalling 440 million yuan (65.5 million U.S. dollars). A total of 720 people were detained and close to 6,500 were held accountable.