International Ozone Protection Day, or World Ozone Day, is marked every year on 16 September – the date the Montreal Protocol on Substances that Deplete the Ozone Layer (the Montreal Protocol) was signed in 1987. This HillNote provides an overview of the progress made through the Montreal Protocol to reverse damage to the ozone layer caused by human-made synthetic substances. The Montreal Protocol is often cited as an example of the progress that can be made on environmental issues through ...| HillNotes