Beijing's new "green police squad" has launched its first joint crackdown on polluters with environmental protection inspectors.

Officers with the squad - part of the Beijing Municipal Public Security Bureau - have been helping environmental protection inspectors carry out surprise checks on manufacturing companies since Feb 27, with the campaign set to last through March.

"The joint inspections will focus on major industries discharging airborne pollutants, such as printing houses and furniture factories, and also diesel trucks," said Zhao Zhiwei, deputy director of the Beijing Environmental Inspection Team.