A coastal view of the waters in Zhoushan. [Photo provided by Zheng Yu for Tide News]

Residents in Zhoushan, East China's Zhejiang province, woke up to an unusually clear blue sea as the normally yellow-tinged waters turned glasslike and bright in early September. 

This rare phenomenon, known locally as "Zhoushan Blue", is expected to last only a short time, drawing crowds eager to capture the view.

Zhoushan, located east of Hangzhou Bay near the estuaries of the Yangtze and Yongjiang rivers, has waters that are typically clouded by sediment carried from the mainland and stirred by tides. 

Experts explained that water clarity depends on the level of suspended sediment. Recently, weak winds and higher temperatures have stabilized water layers, preventing sediment from rising. At the same time, prevailing summer southerly winds have limited the southward movement of silt from the Yangtze estuary.

Over the weekend, many visitors flocked to coastal viewing spots to see the vibrant blue waters of the East China Sea. Tourists and residents alike took photos and shared the fleeting sight, which has become a seasonal attraction known for its dreamlike beauty.