The talks represent a warning to local governments, reminding them to pay more attention to environmental protection, said Zou Shoumin, director of the ministry's Environmental Supervision Bureau.

According to the recently strengthened Environmental Protection Law, the leaders of governments are responsible for the environment and should resign if pollution results in serious consequences.

However, the bureaus of environmental protection in cities and counties face obstacles in implementing tough punishments on polluters, because they are branch departments of the governments and receive leadership from the government, said Zhou Ke, professor of environmental protection law at Renmin University of China.

"The direct talk from the ministry to local governments has been a good way to make up for defects in the administration system," he said.

This round of talks is the fourth since the new minister, Chen Jining, took office just two months ago.

Before Zhumadian, the ministry has talked with mayors from Linyi, Shandong province, and Chengde and Cangzhou, Hebei province, about pollution from illegal companies. Those three conducted thorough inspections and shut down illegal polluters after their talks.

More cities appear to be enhancing their fight against pollution before being lined up for talks.

For example, Beijing updated its emergency plan on serious air pollution on Monday. The plan lowered the standard for launching alerts. The city will tighten supervision on polluting companies and issue more frequent restrictions on air pollutant emitters this year.