Polar stratospheric cloud is formed over Antarctica during ..A.. Here, A refers to

In winter, special type of clouds are formed called polar stratosphere clods are formed over Antarctica. These polar stratospheric clouds provide surface on which chlorine nitrate formed, gets hydrolysed to form HOCl. It also reacts with HCl to give Cl2. 2 2 3 2 2 3 ClNO (g) + H O(g) HOCl(g) + HNO (g) ClONO (g) HCl(g) Cl (g) + HNO (g) -> -> When sunlight return to Antarctica in the spring, the sun’s warmth breaks up the clouds and HOCl and Cl2 are Photolysed by sunlight. UV 2 HOCl(g) OH(g)+Cl(g) Cl (g) 2Cl(g) -> -> The chlorine radical thus formed, and depleted the O3 layer.