North China's Tianjin Municipality issued more than 4,600 pollution fines last year, tripling the number in 2016, with a total value of 220 million yuan (33.8 million U.S. dollars).
The value of the fines increased by 139 percent over 2016, said Yang Yong, an official with the municipal environmental protection bureau.
Enforcement workers were mobilized to inspect more than 34,000 companies in 2017, with the fines the heaviest compared with previous years, said Jia Chunning, head of the municipal environmental inspection enforcement team.
Average density of PM2.5 in Tianjin was 62 micrograms per cubic meter of air in 2017, meeting the goal set by the State Council, the Ministry of Environmental Protection said Wednesday.
The density dropped by 10.1 percent year on year, and by 35.4 percent compared with 2013, the ministry said on its website.