A college student displays a poster of the earth being surrounded by plastics during the launching ceremony of 2010 Earth Hour Changsha in Changsha, capital of central China's Hunan Province, March 21, 2010. [Xinhua]

Two college students simulate the scene of hunting a cowfish during the launching ceremony of 2010 Earth Hour Changsha in Changsha, capital of central China's Hunan Province, March 21, 2010. [Xinhua]