Workers have this week begun laying the tunnel's deepest section, set at over 40 metres below sea level.
The tunnel is being built as part of a 24km cross-sea highway project that is being built to improve transport links in the Guangdong-Hong Kong-Macao Greater Bay Area. The 6.8km undersea tunnel consists of 32 immersed tubes and a closure joint.
Upon completion in 2024, the Shenzhen-Zhongshan cross-sea highway will shorten the travel time between Shenzhen and Zhongshan from two hours to just 30 minutes.
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