This is thinning of the ozone layer, that is present in the stratosphere due to the release of the ozone-depleting substances (ODS) by human activities.
The thinning is also called an ozone hole.
Ozone gas protects living organisms by absorbing the harmful ultraviolet (UV) radiation coming from the sun.
Harmful effects of the ozone layer depletion:
Diseases like skin cancer are caused due to exposure to UV rays.
Diseases like cataracts and other diseases are also caused by ozone layer depletion.
Life on the earth will eventually get destroyed if the ozone depletion is not corrected.