摘要：Increasingly, water scarcity is described as a major challenge facing the world. However, its definition remains a controversial issue. For instance, water scarcity is not an absolute concept. Communities truly facing water scarcity are those where basic human requirements can only be satisfied by some very basic changes in life style and/or levels of living. Developing new supplies and improving water management will not provide enough water, given existing water use patterns. Only a limited number of countries fall in this category. A larger number of countries face water scarcity because they need to make some basic changes in their water management including, in some cases, infrastructural changes to facilitate management. Another group of countries have water scarcity and will need to make both management changes and infrastructural investments to develop their water supply.
