BEIJING, May 5 -- China's environmental protection bureaus dealt with 66 cases that resulted from public tip-offs in January, the Ministry of Environmental Protection said on Monday.

Of the cases, which were reported via the ministry's hotline "12369", 52 consisted of illegal activities, the ministry said. Fourteen cases were repeat reports.

Jiangsu, Hebei and Shandong provinces were the top three regions that had the most tip-offs.

According to the ministry, 31 cases related to air pollution and 20 were about project examinations and approvals. Cases also covered water and noise pollution and solid waste.

The ministry said that the illegal activities had been dealt with in accordance with the law, including immediate corrections, ceasing production, fines and closures.