“Earth Day” is celebrated annually on 22 April to demonstrate support for environmental protection. This international event aims to invite people around the world to create a clean, simple and peaceful living environment. Earth Day was initiated in the 1970s in the United States and became an international event in the 1990s celebrated by environmentalists all over the world as an environmental protection promotional event. On the Earth Day, people from all nations promote and realise their environmental protection initiatives and ideas in various ways.