This has been a problem for quite some time, and is only projected to get worse. Water is, of course, not optional and, if all you have to drink is contaminated, then drink you must. It is rare, now, for such a large region to have water supplies so severely contaminated. I believe the situation will become worse, particularly in developing countries where rampant industrial growth will probably overburden any existing pollution controls and where environmental degradation, such as loss of wetlands and deforestation of slopes, will create flooding situations, loss of topsoil, reduced ability of the environment to naturally cleanse water supplies. In addition to contamination, existing water supplies are being drawn down at alarming levels. In China, current water usage exceeds the capacity for replenishment. Ancient aquifers are being depleted at unsustainable rates in China, Inda, the mid-Western U.S., and some Middle Eastern countries. These aquifers take thousands of years to recharge. The largest use of water is agricultural irrigation. Yet, thousands of miles of irrigation channels run through hot, arid regions, uncovered and subject to loss through evaporation. Simply covering these channels could save billions of cubic feet of water per year. Alternative tilling methods and soil- and climate-appropriate crops can further reduce the strain on water supplies. Use of these methods is sporadic, however. I'm beginning to believe that the next world war will be fought not over energy resources, but over water resources.