New Delhi, Oct. 20 -- Urban migration relies on unseen networks that shape cities and support population shifts.

Contemporary migration is not merely the movement of people to cities. It is the movement of whole systems to operate behind the curtains to facilitate the movements. From transportation to housing to managing resources, cities are constructed with stepped-up foundations that keep the cities running with ease, regardless of the continuous stress.

In most cities, the behind-the-scenes support causes growth to come naturally and practically without effort. Roads, information grids, storage, and utilities all cooperate to develop stability with increasing populations. The result is the balance that lets societies respond to dema...