Earth Day is observed every 22 April — a Wednesday in 2026 — in more than 190 countries. It's the world's largest environmental event. But it began as a single day of protest in the United States. Here's the history.
See the Earth Day holiday page or the global holiday calendar.
Why is Earth Day on April 22?
The first Earth Day was held on 22 April 1970 in the United States. It was conceived by US Senator Gaylord Nelson as a nationwide environmental "teach-in" — a day of education and protest about pollution and environmental damage.
The date was chosen partly because it fell between spring break and final exams, maximising student participation.
A turning point for the environment
The first Earth Day drew an estimated 20 million Americans into the streets — about a tenth of the US population at the time. The scale of it is widely credited with launching the modern environmental movement and helping lead to:
- The creation of the US Environmental Protection Agency (EPA) later in 1970, and
- Landmark laws like the Clean Air Act and Clean Water Act.
The growing concern had been fuelled by events like the 1969 Santa Barbara oil spill and Rachel Carson's influential 1962 book Silent Spring.
Going global
In 1990, Earth Day went international, mobilising people in around 140 countries. Today it's coordinated worldwide and observed in more than 190 countries, with each year drawing attention to environmental themes.
Quick answers
Why is Earth Day on April 22? The first Earth Day was held on 22 April 1970 in the US — the date was chosen to maximise student participation.
Who founded Earth Day? US Senator Gaylord Nelson organised the first Earth Day in 1970.
Why is Earth Day important? It's credited with launching the modern environmental movement and helping create the US EPA and major environmental laws.
When is Earth Day 2026? Wednesday, 22 April 2026 — it is always 22 April.