<prompt> False statement regarding chlorination of water:Water should be free from turbidityChlorine demand of water should be estimatedContact period of at least 2 hours is essentialRecommended residual free chlorine level is 0.5 mgliter  <response>: Refer: K. Parks Textbook of Preventive and Social medicine, 24th edition, pg no: 765, 766Recommended minimum contact period is 1 hour for chlorinationPrinciples of chlorinationWater should be clear, turbid freeChlorine demand should be estimated, which is the amount of chlorine needed to destroy bacteria, oxidize all organic matter, neutralise all ammoniacal substances in waterBreakpoint chlorination The point a which chlorine demand of the water is met Free chlorine begins to appear in water, if further chlorine is added beyond breakpointRecommended minimum contact period is 1 hour for chlorinationRecommended Residual chlorine for drinking water is 0.5 mg litreFor water bodies, post disaster 0.7 mg litreFor swimming pool sanitation, it is 1.0 mg litre 