The destruction of ozone layer is chemical change. The destruction/depletion of ozone layer takes place in presence of chlorofluoro carbon (CFC). The Cl atoms of chlorofluoro carbons can destroy ozone molecules as shown below.
Cl + O3 → ClO + O2 – The chlorine atom changes an ozone molecule to ordinary oxygen
ClO + O3 → Cl + 2O2 – The ClO from the previous reaction destroys a second ozone molecule and recreates the original chlorine atom, which can repeat the first reaction and continue to destroy ozone.
As during the reaction, ozone molecules destroy and oxygen molecules form. So new chemical substances are formed by consuming the starting material hence it is a chemical change.