In winter season, special type of clouds called polar stratospheric clouds are formed over Antarctica. As a result, less depletion of ozone layer takes place due to reactions,I) ClONO2+H2O→  HOCl+HNO3 II)  ClONO2+HCl→  Cl2+HNO3 III) Cl•+O3→  ClO•+O2IV) CH4+Cl•→  C•H3+HCl