NANJING — Construction of a tunnel has started under Taihu Lake in East China's Jiangsu province. It will be the longest and widest underwater highway tunnel in China.

The Jiangsu provincial transport department said Tuesday that a 43.6-meter wide highway tunnel on Changzhou-Wuxi Highway will run for 10.8 kilometers under the lake.

Xia Wenjun, head of the project, said the tunnel is scheduled to open in 2021.

"Taihu Lake is a famous scenic place. Tunnel construction must not impact on the lake's environment," said Xia.

Construction of the highway started in June 2017 and is expected to cost 15.91 billion yuan ($2.4 billion).