Newcomers to India’s big cities will be familiar with the experience of getting helplessly lost in unmarked, haphazardly planned streets. Finding a destination usually requires asking whoever is on the street – a vegetable seller, security guard or befuddled pedestrian – where to go.
Locating a house in a residential neighbourhood can also be an ordeal. Houses are marked by a jumbled system of letters and numbers that are not always ordered in sequence.

