HARBIN, Dec. 24 (Xinhua) -- Harbin, China's "ice city" in the far northeast, has seen a record number of air passengers this year, according to the Taiping International Airport, the city's only airport.

The annual passenger throughput of the airport in the provincial capital of Heilongjiang in 2018 crossed the threshold of 20 million on Monday, a new historical high and nearly double the figure from five years ago.

"The 20 million figure is a milestone for us, laying a solid foundation of building Harbin's airport into an international aviation hub," said Wang Yanzhong, general manager of the Heilongjiang Airport Management Group.

The airport attributed the fast air aviation development to the booming local tourism, ever-growing economic and trade exchanges between China and foreign countries, and the improved aviation infrastructure and services.

First founded in 1979, the airport operates 185 domestic and foreign air routes linking 109 cities.

The airport is currently undergoing expansion. The annual throughput of passengers and goods is expected to surpass 42 million and 400,000 tonnes in 2025.

Known as an "ice city," Harbin has gained international attention for its increasingly popular winter extravaganza, which features massive, elaborate ice sculptures, competitions and winter sports.