BEIJING -- The entire tunnel of Beijing Subway Line 17 was drilled through after the middle section of the tunnel was bored through on Monday, its builder China Railway 14th Bureau Group Corporation Limited announced.

Beijing Subway Line 17 is a major transportation artery that runs north to south in the Chinese capital, where about 21.9 million people live.

With a total length of 49.7 kilometers, Line 17 is designed to have 21 stations. The northern and southern sections of the line opened to traffic in 2023 and in 2021.

Once the entire line is operational in the future, it is expected to alleviate traffic pressure on Line 5 and Line 10.