More than one-fourth of the global elephants population has been killed within the last decade, the United Nations Environment Programme (UNEP) said Sunday as it marked World Environment Day, according to dpa. Celebrations for World Envirnment Day were being held in Angola, where a government agency has been created to put an end to environmental crime, including the killing of elephants, Angolan Vice President Manuel Domingos Vicente said. There are about 470,000 African and 40,000 to 50,000 Asian elephants left in the world, according to the World Wildlife Fund. Environmental crime cost the world an estimated 258 billion dollars last year, 26 per cent more than the year before, UNEP and Interpol said in a joint report Saturday. Environmental crime includes illegal wildlife trade, corporate crime in the forestry sector, illegal gold and mineral exploitation, illegal fisheries as well as the trafficking of hazardous waste and carbon credit fraud.