India, July 22 -- Pigeons occupy the bronze statue of Maharaja Ranjit Singh, plus the adjacent traffic lights, and every ledge that can hold a bird. The flyover begins near this statue at Barakhamba, from which it takes its name.

Most Delhiwale experience the Central Delhi flyover through a windshield. That is a mistake. It is best experienced on foot. And this infrastructural utility is truly uncommon, for it links New Delhi and Old Delhi. The walk takes barely half an hour. Yet, the city changes steadily under your feet.

Traffic here never stops. Cars, motorcycles and autorickshaws stream past. Mixed among them are handcarts loaded with pipes, rods and sacks of cement. This humid evening, an elderly labourer is pushing a cart loaded w...