As he walks along the Metro pillars on Panchkuian Road that reverberate with the sound and the weight of the Metro each time a train passes overhead, Gupta follows the pillars to mark his route.

The pillars are the new postal address, the new landmark, and new reference point for Delhiites who live along Metro corridor. And they have made his job simpler, Gupta says.

The Delhi Metro Rail Corporation started to number the pillars to make maintenance work easier. In case of an accident, or a pillar developing cracks, it would be easier to locate the pillar through serial numbers, the officials thought. But this was a use they never foresaw. “It is Delhi’s new form of address, beyond the codes,” Gupta says. “It is so much easier now — I just follow the pillar’s serial numbers and don’t have to stop and ask for directions.”

Ashish Kumar, director of the General Post Office at Gol Dak Khana, says the pillars work as a good landmark. “They are additional information that help our people,” he says. “Unlike other countries, we do not have street numbers, so sometimes addresses are a little tricky.”

In yet another part of the city, the pillars have found their way on to business cards. In Shadipur, where Metro runs through a road choked with traffic and tiny shops jostling for space, Harvinder Singh had the brainwave three years ago when the Dwarka Metro line was flagged off. The owner of Raja Speaker Shoppe added an extra line — Opp. Metro Pillar No. 250 — on his business card.

“It is common sense,” Singh says, “for what better than to have the pillars as landmark? All shops have done this now.”

Sushil Chadda, another shopkeeper, says the locals earlier indicated Shadipur Depot or the post office as landmarks. But it was confusing, and the numbering system isn’t always in order. The serial numbers on pillars are a foolproof way.

On Shahdara line, near Pitampura in West Delhi, Rajiv Yadav, a watchman, knows how to direct the police patrol to a crime spot. Earlier, the police would get confused and keep going around the area, he says, but a couple of months ago, when a chain snatching occurred his block, he called the police in, indicating the Metro pillar numbers.