Only four of the bridge's eight lanes will initially be operational, underlining the many risks and pitfalls that pave such mega projects in India, where the race to build world class infrastructure has also been slowed by an economic meltdown.

The 5.6 km-long (3.5 miles) Bandra Worli Sea Link, which may handle nearly 100,000 vehicles daily, will help wealthier residents skip nearly two dozen traffic lights and cut more than half an hour in the commute to the business hub in the south.

But the bridge was plagued by bureaucracy, cost overruns, disputes between the state and contractors and litigation by residents and fishermen worried about its impact on environment and livelihood.

There were many challenges and lessons in building this bridge, said Ajit Gulabchand, chairman of Hindustan Construction Co, which struggled to raise funding for the project after numerous delays and because of the financial crisis.

India estimates it needs $500 billion by 2012 to upgrade its congested ports, potholed roads and inadequate utilities, which have suffered from chronic under-investment, an undeveloped capital market and tussles over subsidies and land ownership.

Easing regulations and a booming economy had drawn eager local and foreign investors to the table, but just as it seemed the public-private partnership model would ease India's infrastructure woes, the financial crisis turned the tap off.

Dozens of projects across the country, including several in Mumbai, have stalled, although the new Congress-led government is expected to announce several measures to boost infrastructure spending in its inaugural budget next week.

As a prelude, a spectacular fireworks display lit up the cable-stayed Mumbai bridge in the Arabian Sea against the night sky, cheered by hundreds on rooftops and alongside parked cars, many of whom are willing to pay the 50-rupee ($1) one-way toll.