An environmental worker shows algae that was separated from algae-laden waste water in Chaohu Lake, Hefei, East China's Anhui province, on June 4, 2013. The blue-green 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. [Photo/Xinhua]