Vessels engage in pollution clean-up exercises, part of a China-Russia joint emergency drill on Heihe River between China's Heihe city of Northeast Heilongjiang province and the Russian city of Blagoveshchensk on Sept 17. The third large-scale China-Russia joint drill on border rivers involves about 200 soldiers and 23 vessels. [Qiu Qilong/Asianewsphoto]