Having lived in a hot, humid and perenially water-starved seaside town for a long time, I wish something like this gadget: http://www.elementfour.com/ were more widely available. I am not sure if it is environment friendly in its operation, but it can;t be dirtier than the process of bringing drinking water to the city by rail as the Chennai MMWSSB (there's a fine Indian piece of crap bureaucratic name) has been doing for more than twenty years.
Let's see if this thing becomes popular in India's coastal cities . . .