Efforts have been intensified to tame the environmental pollution in northern China, including in the cities of Beijing and Tianjin, and in Hebei province.

In Beijing, coal-fired boilers have been banned in major downtown areas.

A total of 300 polluting enterprises in Beijing will be transformed or closed down, and cement production capacity will be reduced to 5 million tons.

In Tianjin, workers use infrared devices to monitor emissions from petrochemical plants in the city.

Wen Wurui, head of the Tianjin Environmental Protection Bureau, says the goal is to control pollution at its source.

"According to the requirement that pollution should be controlled at the source, we have identified all the sources of contamination in the city. The number of sources has reached 27,000. We also have taken strict control measures and set up management systems to make sure that we can control pollution from the source."

In Hebei Province, the authorities have begun solving the water pollution issue in Baiyang Lake.

As one of these efforts, fish farming has been banned in the lake.

This has improved the quality of the water flowing from the lake into the Yongding River in Beijing over the past two years.