Quincy Jones, Indian megaindustrialist R.N. Tata and Kevin McGovern (the founder of SoBe beverages) and others have formed an organization called The Water Initiative to bring point-of-drinking water purification devices to emerging nations. Various parts of the world -- Australia, Southern California, Beijing -- are facing severe water shortages, but it's particularly acute in rural India, Africa and Latin America. Not only do farmers not have enough water for their crops, many are sick from drinking infected water. Approximately half of the hospital beds in the world are filled with people inflicted with water-borne diseases. The Water Initiative will seek to develop and then deploy purification devices that can be used by individuals in villages. Why not try to develop large desalination and purification plants? Those cost quite a bit and much of the water gets re-infected or lost during delivery, and that's where pipes actually exist to deliver water. Centralized purification also sanitized laundry and irrigation water to drinking levels, which isn't necessary. In India, many consumers get their drinking water from trucks or machines in a store. You can imagine some of the many buildings and retail outlets associated with the Tata conglomerate coming in handy here. On the other hand, portable purifiers have to worry about things like membrane fouling and breakdowns. I'll be writing more on this organization in the future, particularly on what sort of devices they have in mind. There are several. Students under Dan Kammen at UC Berkeley a few years ago created a portable water purifier that does the job with UV lights.  Porifera, meanwhile, has come up with a carbon nanotube membrane that can purify water without a lot of external pressure or energy. It's easy to maintain too. (More on them at the link.)