India, April 18 -- There must be a tap somewhere. The cramped lane is, after all, called Gali Nal Wali. Yet no nal, or tap, shows up in this dark street in Old Delhi. At the entrance, two guesthouses flank the alley. One bears a large painting that briefly transports you to some town in Luxembourg or Netherlands-trams, elegant facades, buildings in a European style. The lane is wide at first, then narrows. It grows darker as the lane further constricts, the buildings on both sides blocking out the sky. As in many Old Delhi lanes, the gali is lined with arched doorways and slanting staircases-until you reach a building unlike the rest. The interior here is something! It is packed with thousands of egg crates. The structure itself stands out:...