Two unidentified children play in front of their house in Makoko, an area in Lagos, Nigeria, Thursday, June 5, 2003. The World Health Organization (WHO) used World Environment Day on Thursday to insist every human has a right to a clean water supply.

More than a billion people have no access to safe drinking water and one in three have no adequate sanitation. According to the WHO, more than 3,000 children under the age of five die each day as a result of diseases caused by poor access to safe water and sanitation.