The government has banned hotels and resorts along major rivers in southeastern Jiangxi province to preserve Poyang Lake, China's largest freshwater lake, the South China Morning Post reported. In addition to the hotel ban, about 150 polluting factories located within a kilometer of the rivers would be closed and 50 livestock farms would be moved. Poyang Lake is one of the mainland's last sources of potable water. Authorities took action after provincial environmental agencies found the proportion of polluted water in the lake had doubled since last year to 17.9%. The lake is one of four major freshwater lakes in China. The other lakes, including Tai Lake in Jiangsu province, suffered from algae outbreaks caused by industrial pollution this year. Tai Lake's algae bloom caused water shortages to the city of Wuxi in June.