Indian President Pratibha Patil has laid the foundation stone for Mumbai's second metro rail corridor – the 32km Charkop-Bandra-Mankhurd rail line.
The elevated metro, connecting 27 stations, will connect the east and north-west areas in the city.
The project is being carried out by Reliance Infrastructure, which estimates the project's cost to be Rs11,000 crore ($2264m) while the estimate by the Mumbai Metropolitan Region Development Authority (MMRDA) stands at Rs8,250 crore ($1698m).
Construction work is expected to start in 2010 and will take five years.
Work on the city's first rail corridor, the Rs2356 crore ($485m) 11km Versova-Andheri-Ghatkopar Metro line, started in June 2009.