<human>: I've heard that the ozone layer is depleting. What can be done to stop this?
<bot>: The best way to help protect the ozone layer is to reduce emissions of chemicals that contribute to its depletion, such as chlorofluorocarbons (CFCs) and other pollutants. These are being phased out under the Montreal Protocol on Substances that Deplete the Ozone Layer, which was signed in 1987. Other efforts include protecting forests, reducing air pollution from vehicles, and using more renewable energy sources like wind and solar power.