Earth Day 2021: Slogans, quotes, messages and wishes to send on this day Earth Day is observed on April 22 every year and dedicated to Mother Earth and the theme for Earth Day 2021 is "Restore Our Earth". File photo Updated: Apr 22, 2021, 07:10 AM IST Earth Day is observed on April 22 every year and dedicated to Mother Earth. The theme for Earth Day 2021 is "Restore Our Earth and it ''focuses on natural processes and emerging green technologies that can restore the world's ecosystems. In this way, the theme rejects the notion that mitigation or adaptation are the only way to address climate change.'' Earth Day is observed on April 22 since 1970. In 1990, Earth Day became an ''environmental movement, working with more than 75,000 partners in over 192 countries to drive positive action for our planet''.