The Ministry of Environmental Protection on Friday publicized seven cases in which companies have been punished for faking pollution monitoring data.

The ministry has recently strengthened inspection of monitoring devices and found instances of companies falsifying records of their emissions.

In April, a coking plant in the city of Xingtai in North China's Hebei province was found to have "maliciously discharged pollutants" and to have fabricated monitoring data.

Xingtai's environmental bureau fined the company 2.45 million yuan ($400,500) and two members of its management team were detained for seven days.

A steel rolling company in the city of Xinyang in Central China's Henan province was found to have tampered with devices taking samples of its discharges, masking how polluted these discharges were. The company was fined 90,000 yuan and two of its executives were detained for 10 days.