A man sits on a pile of algae as he rest after a swim at a bathing beach in Qingdao, Shandong province July 7, 2008. Thousands of Chinese troops and volunteers should clear unsightly algae from competition areas at the Qingdao Olympic sailing venue by Thursday, an official said. REUTERS/Nir Elias 

A local boy sits in a pile of algae as his friend runs on top of it at a beach in Qingdao, Shandong province July 6, 2008. China's resort city and venue for the Olympic sailing is on a war footing, with thousands of troops and common volunteers battling to clean the city's biggest ever algae bloom before the Games. REUTERS/Nir Elias 

A tourist from Tianjin is covered with sand as he rests next to a pile of algae on a beach in Qingdao, Shandong province July 7, 2008. Thousands of Chinese troops and volunteers should clear unsightly algae from competition areas at the Qingdao Olympic sailing venue by Thursday, an official said. REUTERS/Nir Elias 

People play volleyball on a beach, which is partly covered with algae, at the coastline of Qingdao in Shandong province July 4, 2008. China has thrown 10,000 people and 1,200 vessels into the fight to clean up a huge algae bloom that has turned large swathes of Qingdao's offshore waters green and encroached on a third of Olympic sailing waters. REUTERS/Nir Elias