Which problem does the montreal protocol address

Ozone depletion

Explanation:

Release of ozone depleting pollutants in atmosphere has led to ozone hole. Ozone is present in stratosphere of the atmosphere of earth and serves to absorb harmful UV radiations of sunlight. The adverse effects of ozone depletion of human health (as severe as skin cancer) led to acceptance of Montreal protocol. The protocol aimed to check the release of ozone depleting substances in atmosphere to prevent any further ozone thinning.