The theme for this year's World Environment Day, which will be held on 5 June 2021, is ecosystem restoration. Ecosystems are defined as the interaction between living organisms (plants, animals, people) with their surroundings. This includes nature, but also human-made systems, such as cities or farms.
World Environment Day 2021 will see the launch of the UN Decade on Ecosystem Restoration, which urges everyone, governments, corporations and citizens, to do their part in helping the planet.
Source: World Environment Day, May 2021