Several fishing boats at Chaohu Lake are covered in blue-green algae in Hefei, east China's Anhui Province, on June 4, 2013. The algae can lead to loss of oxygen and result in fish deaths. As one of China's five largest freshwater lakes, Chaohu Lake has been plagued by massive blue-green algae outbreaks in recent years, as the rising domestic and industrial sewage from the bourgeoning population and industry in adjacent regions led to high levels of nitrogen and phosphorus in the water. In order to improve the water quality in Chaohu Lake, Anhui province has launched a program to connect Chaohu Lake with Yangtze River, China's longest river, and Huaihe River. [Photo/Xinhua]