Some 2,546 companies, or 66.2 percent of those examined, violated environmental standards during the second round of air pollution inspections, China's environmental authority announced Saturday.
From April 28 to May 11, the second round of air pollution inspections examined 3,846 companies across the country, according to the Ministry of Environmental Protection (MEP).
Major problems included excessive emissions and failure to install or improper operation of pollution control equipment, the MEP said in a statement.
The central government is fighting pollution and environmental degradation after decades of growth have left the country saddled with problems such as smog and contaminated soil.
Chinese enterprises were fined around 264 million yuan (38 million U.S. dollars) for violating standards in the first quarter of this year, the MEP said last month.
The ministry issued punishments in nearly 5,000 cases related to violations of environmental protection regulations and laws in Q1, up around 200 percent year on year.
In 224 cases, companies had to pay between 10,000 and 100,000 yuan per day after failing to rectify violations within the time frame set by the MEP.