<prompt> Refer to the passage below and then answer the question afterwards in the same language as the passage: Passage: The treaty is structured around several groups of halogenated hydrocarbons that deplete stratospheric ozone. All of the ozone depleting substances controlled by the Montreal Protocol contain either chlorine or bromine substances containing only fluorine do not harm the ozone layer. Some ozone-depleting substances ODSs are not yet controlled by the Montreal Protocol, including nitrous oxide N2O For a table of ozone-depleting substances controlled by the Montreal Protocol see:For each group of ODSs, the treaty provides a timetable on which the production of those substances must be shot out and eventually eliminated. This included a 10-year phase-in for countries identified in Article 5 of the treaty. Question: What group of substances depletes stratospheric ozone.  <response>: ma-halogenated mahydrocarbon 