Conservation of the ozone layer and its depletion was addressed in the following protocol:

The Montreal Protocol on Substances that Deplete the Ozone Layer is a landmark international environmental treaty adopted in 1987. It was specifically structured to regulate and phase out the global production and consumption of ozone-depleting substances ($\text{ODSs}$), such as chlorofluorocarbons ($\text{CFCs}$), to heal the stratospheric ozone layer.