Treatment of water with chlorine to kill the germs and bacteria in it is called chlorination. Passing ozone through water to kill the germs and bacteria is called ozonization. Though both chlorine and _x000D_ozone through can kill the germs and bacteria, ozone is more effective than chlorine for the same purpose. This is because when the relative proportions of ozone and chlorine required are compared, ozone is required in much lesser proportion when com- pared to chlorine. Moreover, chlorine is generally used in excess quantity, and hence imparts little colour to the water and also causes minor health problems. Therefore, ozone is more effective than chlorine.
