Beijing will begin building its second airport next year in a southern suburb to ease the burden of the current Capital International Airport, the second busiest airport in the world.

The new airport, costing at least 70 billion yuan ($11.26 billion), will be put into use in 2018, Zhu Wenxin, assistant director of the airport construction office, told a Beijing forum yesterday.

"The airport will have six civil-use runways and can handle 45 million passengers a year in the beginning and up to 70 million passengers by 2025," Zhu said.

He said the new airport is necessary because the Capital International Airport is running nearly at full capacity.

Moreover, Beijing is the only one among the world's major cities with just one airport. London has five airports; Paris has two and Tokyo also has two.

The new airport should meet the demand of domestic airlines because all the routes to or from Beijing are among the most popular, said Zhang Wu'an, a spokesman for the Spring Airlines.

"The company has begun talking with the new airport management to get berths at the airport," Zhang said.

A 37-kilometer railway will also be built linking downtown Beijing and the new airport in a 30-minute drive, according to the city's urban planning department.