A social activist shows his painted back as he takes part in an environment awareness program on the occasion of World Environment Day in the northern Indian city of Chandigarh June 5, 2008. The United Nations urged the world on Thursday to kick an all-consuming addiction to carbon dioxide and said everyone must take steps to fight climate change. World Environment Day, conceived in 1972, is the United Nation's principal day to mark global green issues and aims to give a human face to environmental problems and solutions. [Agencies]