Boats carry out cleaning work in the area affected by oil spill in Dalian, a coastal city in northeast China's Liaoning Province on July 19, 2010. More than 500 fishing boats were set off Monday to clean up the crude oil that gushed into the sea after an oil pipe exploded at Dalian Xingang Harbor. Another 4 patrol boats kept monitoring the diffusion of oil and cleaning work, while laying out more protective boom. [Xinhua]