More than 700 people were detained and 6,454 fined in China for violations of environment-related regulations in 2016, according to government data.
The government started to look into 33,000 cases and imposed fines amounting to $63.6 million as a result of the central government's inspections in several provinces and municipalities and major cities such as Beijing and Shanghai.
The government also reported that pollution caused by PM2.5 was less in 2016. The average density of PM2.5 in 338 cities lowered by 6 percent.
The national plan on environmental improvement for the 13th Five-Year Plan was launched last month.
The central government also gave the Ministry of Environmental Protection additional powers to send inspection teams anywhere in the country. The ministry now has the authority to conduct meetings with senior local officials.
It was only the second Chinese agency to be granted such authority.
Ma Jun, director of the Institute of Public and Environmental Affairs, said, "We talk about local government interference in environmental enforcement and these central government investigations can address this problem at the source."
The environment ministry reported that it had fined several state-owned polluters for exceeding emission limits.
PetroChina, the largest oil company in the country, has a subsidiary in the northeastern city of Dalian that was fined a total of $433,644.
"We need to recognize the progress made and this is definitely higher than before, but on the other hand, it is still not enough and is still cheaper than the cost of compliance," Ma said.
He added: "We also don't know if in reality the fine will be paid. Many of them are the darlings of local government, which gives them protection."