India, Jan. 12 -- New Delhi

In Indore recently, sewage contaminated a drinking water pipeline running beneath a residential neighbourhood, killing at least 10 people. Officials blamed the tragedy on a cracked pipe; the angry residents complained of years of negligence.

However, the failure runs deeper-and remains largely unseen.

Above ground, Indian cities are governed by many layers of rules-land use is zoned, building heights regulated, setbacks enforced, and environmental clearances contested and monitored. But below ground, there is no such regime.

So, who governs the city below?

Pretty much no one.

Experts say this vacuum should no longer be ignored as Indian cities dig deeper than ever-for Metro tunnels and road underpasses, p...