Rush hour traffic on Beijing streets. Beijing is one of the world's most polluted cities and poor air quality (File)

The Chinese city of Tianjin has ordered 40 factories to close for nearly two months in an effort to cut air pollution for the Beijing Olympics.

Tianjin, a port city about 150 kilometers southeast of Beijing, will host some of the Olympic soccer matches.

The city ordered the factories to close from July 25 through September 20.  The city has also banned work on major construction sites during the same period.

Beijing has taken similar efforts to improve air quality, including an "even-odd" system based on license plates which aims to take half the city's cars off the roads ahead of the Games.  

Some information for this report was provided by Reuters.