In February, the coordinated development of the region became a national strategy, with the joint treatment of air pollution as one of the main purposes.

"The haze in the region in recent years, is not only a problem for the region itself, but one related to all northern and eastern regions," said Zhang Gui, deputy director for Beijing-Tianjin-Hebei Development Center at Hebei University of Technology.

"The pollution is a result of a growth model featuring high energy consumption and emissions. It must be solved on a regional level," said Zhang.

Results of pollution control in the region are already felt. Take Xingtai City. The city has seen 66 days with good or fairly good air quality this year, 28 days more than the whole of last year.

Beijing and neighbors regularly coordinate on pollution, but they need to improve their information sharing and consultation on alerts and response, said Li Lixin, an official with the Beijing Environmental Protection Bureau.

"In terms of joint regional pollution control, each city or province should first deal with its own problems and then shoulder common responsibilities," said Feng Yinchang, a professor in environmental science and engineering at Nankai University in Tianjin.

"A simple transfer of pollution should be avoided," Feng stressed. Beijing is considering moving some companies to Tianjin and Hebei as it transfers some of its non-capital functions.

China plans a monitoring and warning system to respond to heavy air pollution with more attention given to pollution control in coal burning, vehicles and dust in key regions, according to a revised draft of the Air Pollution Law unveiled in early September. More strict law enforcement is expected.

Despite slight improvements in air quality in the Beijing, Tianjin and Hebei region this year, days of heavy pollution will come again, said Feng.

"It will take a long time for us to realize the ideal blue sky days because the pollution problem will not be solved in three or five years," said Feng. Enditem (Xinhua correspondents Cao Guochang, Kong Xiangxin and Ni Yuanjin contributed to the story.)