A major milestone has been reached in the construction of the world's longest undersea high-speed rail tunnel in eastern China. A giant tunnel boring machine has completed a 6.27-kilometer excavation from the Zhoushan side, reaching its designated meeting point beneath the sea.

The 16.18-kilometer Jintang Undersea Tunnel is a key part of the Ningbo-Zhoushan Railway. Another machine is digging from the opposite side, with the two expected to meet underwater in 2027.

Once the railway opens, the island will be connected to China's rail network for the first time, with the fastest journey from Ningbo taking around 30 minutes, further incorporating Zhoushan with the rest of the busy Yangtze River Delta area.