Ozone layer which is a part of the lower stratosphere has been continuously depleting over years. The ozone layer is a part of the atmosphere that contains high concentration of ozone molecules which absorb the harmful ultraviolet rays from the sun and prevents it from reaching the earth surface. Ozone layer depletion is one of the most significant issues in the present-day world. It is getting worse day by day and has become a threat to global environment as well as human civilization. The main sources of ozone layer depletion are the man-made chlorine related substances such as chlorofluorocarbons (CFCs), bromine, halons, carbon tetrachloride, methyl bromide, hydrofluorocarbons etc. When the ozone layer is significantly thinner over a particular region due to the release of ODS (Ozone depleting substances), it is termed as “Ozone Hole”. The main effect of ozone layer depletion is the increase in ultraviolet rays that reaches the earth surface and makes serious ill effects on human beings, genetic changes, growth on plants, marine ecosystem, damage to possessions etc. Growing concern for ozone layer depletion has led to the adaptation of various policies by various countries to bring down the release of ozone depleting substances at an industrial level as well as individual level. This paper tries to assess the causes and consequences of global ozone depletion and presents some protective measures for preventing further depletion of ozone layer.