BEIJING - The Ministry of Environmental Protection has demanded local environment protection authorities punish enterprises that had fail to initiate emergency response plans to cope with smog, said a statement Tuesday.

The ministry found some polluters continued to operate after teams were dispatched to areas around Beijing to ensure emergency plans were in place.

According to the statement, illegal emissions, coal-burning dust, nonpoint source air pollution and failing to react according to the emergency response plan have been the main problems discovered during inspections.

Some polluting enterprises, including a stone processing factory and several clothing workshops, continued to operate on Tuesday after a red alert, the highest level, was issued in the morning. A red alert means suspension of classes, construction work and limited use of cars.

A car paint workshop in downtown Beijing was sealed up on Tuesday by the city environment protection agency after it received reports of its illegal operation from the public.

In neighboring Hebei Province, the environment protection authority detected a dozen coal-burning enterprises operating illegally.

Inspection teams discovered that nonpoint source air pollution, such as road and construction site dust, remained severe in central China's Henan Province and eastern province of Shandong.

Several cities in Henan were reported for failing to react according to the emergency response plan and several construction sites were still in operation in Shandong.

The Ministry has called strengthened monitor on the air quality of areas around Beijing and tougher supervision on the implementation of emergency response plans.