Many public infrastructure projects in India proceed at a glacial pace or never get off the ground because of bureaucracy, property disputes and apathy.
But when the 65km first phase of the Delhi Metro opened in 2004, it confounded critics.
Delivered ahead of schedule and under budget, the $2.3bn underground railway system also turned out to be clean, run on time, to offer an affordable alternative to commuters and turn a profit, making it a rare model of success.
It also turns out to have been an inspiration. Emboldened by New Delhi's example, other cities plagued by congestion and pollution are pressing ahead with plans for their own metro systems to try to mitigate the effects of the rapid growth of the country's urban populations.
The Delhi Metro has been "a saviour", says G.R. Madan, director of the Mumbai Metropolitan Region Development Authority. "Its success is responsible for the revival of people's interest in metros."
Mumbai, Chennai, Hyderabad, Bangalore and Cochin are planning mass transit systems while Kolkata, home to India's only other underground system, is expanding its 24-year-old metro.
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Adding to the urgency is the growing number of vehicles on Indian roads and fears that the launch this month of Tata Motors ' $2,500 (euro 1,700, pound 1,300) "people's car" will add to congestion.
In Mumbai, the planned $4.3bn 146km metro system is expected eventually to carry nearly 5m passengers daily and "would change the transportation scenario of Mumbai altogether. We've been dreaming of this for the last 40 years," Mr Madan says.
The Delhi Metro says its 280 carriages transport 650,000 passengers daily and siphon 1.5m commuter trips each day off the roads. The result, officials claim, is 1,650 fewer buses on the roads, annual fuel savings of $110m and 30 per cent less air pollution.
The second phase of the Delhi Metro, which will involve $4.25bn in contracts and, like the first, will be financed largely by Japan, requires about 500 train carriages that will carry 2.2m additional passengers a day.
But other cities are still facing significant - and very Indian - hurdles. Construction on an 8.7km extension of the Kolkata Metro scheduled for completion by next June has stalled because one family has refused to vacate land in return for government compensation.
While the Delhi Metro acts as an independent albeit government-backed corporation, others are saddled with bureaucracy.
The Kolkata Metro falls under the jurisdiction of India's railway ministry, which entrails layers of bureaucracy. It is lossmaking, partly because it cannot dictate ticket prices and must wait for central government approval for revenue-generating schemes such as property development and advertising.
The development of the Bangalore's Metro has also been stymied by bureaucracy and apathy since plans were conceived in 1982. The once-sleepy city has since mushroomed into a metropolis of nearly 7m in desperate need of mass transit systems.
"We should have got a metro years ago," says B S Sudhir Chandra, director of planning for Bangalore Metro. "But better late than never."
