Lake Tai is the third-largest freshwater lake in China. It is located north of Shanghai in Jiangsu Province and is approximately 70 kilometers (44 miles) long and 60 kilometers (37 miles) wide, with an average depth of about 2 meters (6.5 feet). The Tai Basin is a very developed region in China and includes the megacity Suzhou, visible east of the lake. Rapid urbanization, population growth, and excessive fish farming have resulted in a large increase of nutrients in the lake. This deteriorates the water quality, causing toxic algae blooms and threatening the safety of the millions of people who depend on the lake as a source of drinking water. May 24, 2019.