Success in the Slums?

A century ago at the marshy edges of what is today Mumbai, Muslim traders from Tamil Nadu and Gujarati claimed land for the beginnings of a hub to process animal skins.

Rural workers were brought in from the traders’ home districts and set up shacks on the wetland. Specialized functions related to the tanning trade were developed in commercially potent proximity to one another, offering new economies of scale. Dharavi, as the migrant district was known, would eventually evolve from a loose network of village-like outcroppings into a giant slum with a stupefying density up to ten times that of the adjacent city of Mumbai, already the most densely populated city in the world.

In an epic narrative of ad hoc development, the countryside labourers recruited to come to Dharavi found themselves in living and working conditions almost any westerner would deem dire. Yet the draw was an opportunity to earn enough additional small coins in an hour to...