The pipes snake around rusty corners of corrugated iron shacks and weave along the narrow alleyways of the Korail slum, terminating at a concrete tank into which they dribble a stream of contraband water.

Korail, a rough-and-tumble place that swallows daylight, is not connected to the public water supply in Dhaka, Bangladesh’s capital, because like most slums its residents occupy land to which they have no legal right.