The <a href="https://en.wikipedia.org/wiki/Montreal_Protocol" id="mw2g" rel="mw:WikiLink" title="Montreal Protocol">Montreal Protocol</a> is signed to protect the ozone layer from <a href="https://en.wikipedia.org/wiki/Ozone_depletion" id="mw2w" rel="mw:WikiLink" title="Ozone depletion">depletion</a>.