A large expanse of blue-green algae is seen floating on the surface of Shuangqiao River, which belongs to eastern half of Chaohu Lake in Hefei, capital of east China's Anhui province, June 22, 2010. The blue-green alga, namely enteromorpha prolifera, presently covers several square kilometers of the river and emitting bad smells due to the hot and arid weather. Local governments have dispatched two vessels to clear the algae from the river and are closely monitoring the potentially harmful algae bloom in Chaohu Lake.[Photo/Asianewsphoto]

Blue-green algae floats on the surface of Shuangqiao River, which belongs to eastern half of Chaohu Lake in Hefei, capital of east China's Anhui province, June 22, 2010.[Photo/Asianewsphoto]