China's Ministry of Environmental Protection on Friday warned the leaders of two heavily polluted cities to take concrete actions to strengthen inspections and impose severe penalties on polluters.

The leaders of the cities of Linyi in Shandong Province and Chengde in Hebei Province were summoned by environmental inspectors.

Inspectors found that 13 of 15 energy-intensive, high-pollution enterprises had violated environmental laws in Linyi. The enterprises were mainly coking and steel plants.

Chengde was the only city in the Beijing-Tianjin-Hebei region that saw worsening air pollution figures last year.

Meanwhile, Beijing will start levying construction dust pollution fees from March 1.

The fee will go directly into a fund managed by the city's finance bureau to support treatment and the monitoring of dust pollution sources in Beijing.