A date, a story.
16 September marks the signing of the Montreal Protocol in 1987, an international agreement to reduce substances that damage the ozone layer. The UN established this observance in 1994. It is an invitation to discover a concrete example of environmental cooperation.
On 16 September 2009, the Montreal Protocol and the Vienna Convention became the first treaties in UN history to achieve universal ratification.
Sources consulted on September 15, 2026.
