Water is the most essential thing for the survival of human being. Despite the fact that water consist 71% surface of the Earth still there are some places which are running out of drinking water. 11 cities of the world are likely under the danger, where there will be no drinking water. Over one billion people lack access to water and another 2.7 billion find it scarce for at least one month of the year. According to 2014 survey of the world’s 500 largest cities estimates that one in four are in a situation of water stress.