Which from following gases causes the depletion of ozone layer in upper atmosphere?

Step-by-step solution

The ozone layer in the upper atmosphere is depleted by substances like chlorofluorocarbons and nitrogen oxides. Nitric oxide (NO) is a significant ozone-depleting agent that reacts with ozone ( O ₃ ) in a catalytic cycle: NO + O ₃ NO ₂ + O ₂ and NO ₂ + O NO + O ₂ . O ₃ + O 2 O ₂ NO acts as a catalyst, regenerating after each cycle to destroy multiple ozone molecules. Although other nitrogen oxides can contribute, NO is the most direct and potent among the options. The correct choice is A .