To strengthen its ecological protection work, Sansha, China's southernmost prefecture-level city, has banned activities near the world's deepest blue hole.

A notice issued on Oct. 8 forbid any institution or individual from conducting fishing or sightseeing activities in the area within 1 nautical mile of the Sansha Yongle Blue Hole, the world's deepest underwater sinkhole, which is located near the Xisha Islands in the South China Sea.

The notice requires relevant departments to enhance education about maritime environment protection. It also stipulates that scientific studies in the area must get approval from the Sansha municipal government.