World Ozone Day 2026: September 16 Theme and Background of the Ozone Layer Observance

Key facts

• World Ozone Day is observed every year on 16 September, and its official name is the International Day for the Preservation of the Ozone Layer.
• The theme for World Ozone Day 2026 is 'Global action for a cooler planet', highlighting the Montreal Protocol and the Kigali Amendment's contribution to climate action.
• The United Nations General Assembly proclaimed 16 September as the International Day for the Preservation of the Ozone Layer on 19 December 1994, and the first observance took place in 1995.
• The date commemorates the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer on 16 September 1987; it entered into force in 1989.
• The Vienna Convention for the Protection of the Ozone Layer was adopted in 1985.
• The Kigali Amendment, adopted in 2016, established a global phase-down of hydrofluorocarbons (HFCs), which are powerful greenhouse gases.
• The ozone layer lies in the stratosphere, roughly 10 to 40 kilometres above Earth's surface, with about 90 percent of atmospheric ozone located there, and absorbs harmful ultraviolet radiation.
• Ozone depletion was mainly caused by human-made ozone-depleting substances such as chlorofluorocarbons (CFCs), used in refrigeration, air conditioning, aerosols and foam production.
• The 'ozone hole' refers to severe seasonal ozone depletion, most notably over Antarctica, not a literal empty hole in the atmosphere.