World Ozone Day 2025

World Ozone Day is observed on 16 September, marking the Montreal Protocol signed in 1987. It explains how science and international cooperation protect the ozone layer that shields life from harmful ultraviolet radiation.

World Ozone Day, formally the International Day for the Preservation of the Ozone Layer, is observed on 16 September. The date marks the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987, a landmark international agreement created after scientists showed that chemicals such as chlorofluorocarbons were damaging the stratospheric ozone layer. Because ozone high in the atmosphere absorbs much of the Sun's harmful ultraviolet radiation, its depletion posed risks to human health, crops and ecosystems. The UN General Assembly proclaimed the international day in 1994, and it has been observed since 1995. The day is often presented as an example of science, diplomacy and industry working together: countries agreed to phase out ozone-depleting substances, later strengthening the agreement as evidence evolved. Activities explain ozone science, celebrate recovery progress and stress the need to maintain compliance and manage replacement chemicals responsibly.

Recognises global action under the Montreal Protocol to protect stratospheric ozone from ozone-depleting substances.

Ozone-science lessons, refrigerant-management awareness, environmental workshops and discussions of Montreal Protocol progress; no religious rituals.

Worldwide UN observance on 16 September. It concerns protective stratospheric ozone, distinct from harmful ground-level ozone pollution.