World Oceans Day reminds every one of the major role the oceans have in everyday life. They are the lungs of our Planet and a major source of food and medicine and a critical part of the biosphere. The purpose of the Day is to inform the public of the impact of human actions on the ocean, develop a worldwide movement of citizens for the ocean, and mobilize and unite the world’s population on a project for the sustainable management of the world's oceans.

https://www.un.org/en/observances/oceans-day