Indian premier Manmohan Singh has launched a metro railway project in the western city of Mumbai (Bombay).
The metro is expected to ease traffic congestion in the city
Work on the $5bn mass rapid transit will begin in October and is expected to be completed by 2010.
A large part of the system will run on elevated tracks while the remainder is underground - the third such system after Calcutta and capital, Delhi.
The system is being seen as the answer to Mumbai's traffic problems and rising air pollution levels.
The Mumbai metro railway system will cover a distance of 146km (90 miles) and link India's financial and entertainment capital with its suburbs.
End of gridlock?
Mr Singh inaugurated the first phase that will link Versova in the west to Ghatkopar in the east - a 11km (6.8 miles) corridor with 12 stations.
"We need new investment in world-class public infrastructure for our cities. We have to invest in public transport," he said.
"Our cities have to become more liveable and more
The government of the western state of Maharashtra and the private Reliance Dhirubhai Ambani Group will share the costs of the corridor with the private company picking up 74% of the tab.
Authorities say the metro railway will drastically reduce travelling time in a city of over 18 million people where traffic gridlocks have begun affecting work.
They say the time taken to travel from Versova to Ghatkopar will be reduced to 21 minutes on the metro railway from over an hour by road.
There has been some criticism of the Metro railway project by the city's environmentalists who say it will mar its skyline.