Option 1 states that both statement I and statement II are individually true and that statement II is the correct explanation of statement I.

Statement I states that chlorine radicals (Cl) initiate the chain reaction for ozone depletion. This is true because chlorine radicals are highly reactive and can break down ozone molecules by abstracting an oxygen atom from them. This initiates a chain reaction where other chlorine radicals are produced, leading to the destruction of ozone molecules.

Statement II states that gaseous hypochlorous acid and chlorine are photolysed by sunlight. This is also true because sunlight provides the energy required to break the bonds in hypochlorous acid and chlorine molecules. This photolysis process generates chlorine radicals, which then go on to initiate the chain reaction explained in statement I.

Therefore, option 1 is correct in stating that both statements are true, and statement II correctly explains statement I. There are no errors in the provided answer.