World Environment Day ('WED') is celebrated every year on 5 June to raise global awareness of the need to take positive environmental action. It is run by the United Nations Environment Programme (UNEP). It was the day that United Nations Conference on the Human Environment began. The United Nations Conference on the Human Environment was from 5–16 June 1972. It was established by the United Nations General Assembly in 1972.
The first World Environment Day was in 1973. World Environment Day is hosted every year by a different city with a different theme and is commemorated with an international exposition in the week of 5 June. World Environment Day is in spring in the Northern Hemisphere and fall in the Southern Hemisphere.
"Stockholm was without a doubt the landmark event in the growth of international environmentalism", writes John McCormick in the book Reclaiming Paradise. "It was the first occasion on which the political, social and economic problems of the global environment were discussed at an intergovernmental forum with a view to actually taking corrective action".