Shanghai drinking water hit by salt tide

Record intrusion of seawater affects about 2 million residents

Shanghai is taking measures to ensure water safety as the city experiences its longest-lasting salt tide in more than 20 years, affecting the drinking water of about 2 million residents.

A salt tide occurs, particularly during an astronomical high tide, when seawater rises and flows upstream into the lower-altitude course of a river, causing the river's water to become salty.