Making Water Everybody's Business looks at water harvesting practices across the world. Aizawl is an overpopulated town in the hills of Mizoram. The water source is a river. Or the ample rain. The wise have built simple systems that direct the rain falling on the roof into clean storage tanks.
Water is no longer a problem.
Cities across the world are heavily concretised. Ironically these cities also have to deal with urban floods during the monsoon. Tokyo in Japan has found a solution to both. It harvests rain. Germany promotes water harvesting and taxes the people based on the water they release into drains.