Steam and smoke clouds rise from a power plant factory in Huai'an city, East China's Jiangsu province, Jan 31. [Photo/CFP]

The Ministry of Environmental Protection has imposed a total fine of 112 million yuan ($18 million) on 160 cases nationwide in the first four months of this year.

After the Environmental Protection Law came into effect, there has been a 515 percent increase in cases in March and April from the first two months this year, Zou Shoumin, chief of Environmental Inspection Bureau of the ministry, told Yicai.com on Monday.

The highest fine of an individual case was 15.8 million yuan on Shaanxi Coal and Chemical Industry Group Co which failed to correct the problem of discharging excessive pollutants. China's central Henan province handled 26 such cases in the first four months slapping a 29-million-yuan fine.

Enterprises have stepped up investment in environmental protection after the strict law enforcement, said Zou.

According to a Xinhua news report, a document titled "Crucial Points for 2015 National Environmental Supervision Work" released in March stressed that various punishments, including fines, impounding of funds or facilities, restraining manufacturing, suspension of operations and administrative detention, should be strictly implemented, and the Environmental Protection Law must be used "fully and precisely."