World Environment Day is celebrated every year on June 5th in more than a hundred countries around the world. This date was adopted by the UN General Assembly, since on that day in 1972, the Environmental Protection Conference was held in Stockholm. The aim of marking is to draw the attention of governments and public to the critical global issues of environmental protection and the need for continuous dealing with these issues. On this day, activities are organized in order to raise ecological awareness about the consequences of certain human activities that endanger life on Earth, such as pollution of water, air, forest ecosystems, extinction of many species, etc. This year, the People's Republic of China will be the host country marking the World Environment Day, the theme of which is "Air Pollution".