Acid rain is caused due to oxides of nitrogen and sulphur reacting with water, oxygen, carbon dioxide, and other chemicals present high in the atmosphere resulting into acidic pollutants. As a result of this pH of rainwater lowers down to 5 resulting in pH changing of lakes and streams. It also reacts with calcium carbonate present in the marbles causing weathering. The oxides of sulphur may also react with 03 present in ozone, thus depleting the ozone layer.