Beijing Capital International Airport has announced extended cooperation with the United Nations Environment Programme (UNEP) in environment protection aiming to promote itself as a low-carbon airport.

The two sides will communicate regularly on a wide range of issues, including green airport buildings, sustainable development and public participation in environmental protection, according to a memorandum signed between them.

"We are delighted to be able to contribute through our expertise to help the airport improve its environmental management,"Ibrahim Thiaw, UNEP deputy executive director, said on Thursday.

"We hope further cooperation with UNEP will help us have more exchanges with international companies," Shi Boli, general manager of the airport, said.

"We will conduct exchanges with some foreign enterprises on environmental protection technologies and learn from some overseas airports in promoting the use of new technologies and energy conservation".

The airport has taken a series of emission-reduction measures in recent years, such as adopting lights that consume less power and introducing clean-energy vehicles, Shi said.

All vehicles used in the airport will be replaced by or upgraded to those driven by clean energy in the future, he said.

The airport handled more than 86 million passengers last year, ranking second in the world behind only Hartsfield–Jackson Atlanta International Airport.