The Commission on Sustainable Development (CSD) was established in December 1992 to monitor and report on the implementation of UNCED agreements. In 1997, the UN General Assembly conducted a five-year review of progress since the Earth Summit. Agenda 21, a comprehensive action plan, guides efforts to address environmental impacts globally, nationally, and locally. The full implementation of Agenda 21 and the Rio principles was reaffirmed at the 2002 World Summit on Sustainable Development in Johannesburg.