Atal Setu History: How India Built Its Longest Sea Bridge

Mumbai’s problem has always been geography. The island city sits at the tip of a narrow peninsula, and in the 1960s everything going to the mainland had to go north, round the harbour, through Thane Creek. In 1963 the US consultancy Wilbur Smith and Associates, in a transport study for the city, suggested a shortcut: a bridge from Sewri, on the island’s eastern shore, across the harbour to Uran on the mainland near what would become the Nhava Sheva port.

The idea did not go far. The mainland opposite was still thinly populated, and the city’s planners chose a cheaper answer to the same problem. The Thane Creek bridge at Vashi, opened in the early 1970s, became the road into the new township of Navi Mumbai, planned from the early 1970s. The harbour crossing, as Swarajya later put it, “went into cold storage, and stayed there for decades.”

It came back in 1981, when a steering group chaired by JRD Tata, then chairman of Tata Sons, recommended a transport link along the Sewri–Nhava Sheva route to decongest the island city. When the project was discussed again in the mid-1980s, its cost was put at about ₹350 crore. That figure would be multiplied roughly fifty-fold before the bridge was finished.

The modern revival began in 2004. The infrastructure lender IL&FS submitted a build-own-operate-transfer proposal. The Maharashtra State Road Development Corporation (MSRDC), which had just built the Mumbai–Pune Expressway, put up its own plan. Neither went ahead. MSRDC’s estimate then was about ₹4,000 crore.

In 2005 MSRDC invited bids, and the Ambani brothers ended up on opposite sides. Anil Ambani’s Reliance Energy, with Hyundai Engineering, quoted a toll concession of 9 years and 11 months. Mukesh Ambani’s Sea King Infrastructure quoted 75 years. Moneylife later called the process “the story of unrealistic bidding”. The Reliance–Hyundai consortium was first disqualified at the technical stage, went to the Supreme Court and won. It emerged as the winner, but the project still did not move. The state called fresh bids in 2008 with a cost of about ₹6,000 crore. Thirteen companies showed interest, and none submitted a bid.

Politics made it slower. In a Congress–NCP coalition, the question of which agency should own the project became a turf war. By the time the dust settled, the estimate was ₹8,800 crore (November 2011), then ₹9,360 crore (August 2012) and ₹9,600 crore (January 2013). A last attempt to find a private builder in 2013–14 also drew no takers. The market was saying the same thing each time: toll revenue alone could not pay for this bridge.

The institutional fix came by government resolution. On 4 February 2009 Maharashtra decided that the Mumbai Metropolitan Region Development Authority (MMRDA) would own and implement the project. On 8 June 2011 it was re-designated a Regional Development Project rather than a transport project. The difference was not cosmetic. A regional development project could be justified by the growth it opened up in Navi Mumbai and Raigad, not only by the tolls it collected.

Then came clearances. The Union environment ministry granted environmental clearance in October 2012 with conditions. The Department of Economic Affairs approved about ₹1,920 crore of viability gap funding in January 2013, and coastal regulation zone (CRZ) clearance followed in July 2013. The hardest part was the forest clearance, because the alignment crossed mangroves and the Sewri mudflats, where tens of thousands of flamingos winter. In 2015 the Forest Advisory Committee held back approval until the impact on the birds was studied. Forest clearance came in January 2016.

What finally broke the logjam was money plus political attention. Devendra Fadnavis, chief minister from late 2014, put the project in his infrastructure “war room”, and in 2016 Japan’s development agency agreed to lend most of the cost. On 24 December 2016, Prime Minister Narendra Modi laid the foundation stone.

Once the private-concession model had failed, the bridge needed patient, low-cost capital. The Japan International Cooperation Agency (JICA) provided it through official development assistance loans on concessional terms with a long repayment period. JICA signed three loan agreements: in March 2017, March 2020 and February 2023. By its own count they totalled ¥242.459 billion, about ₹13,715 crore, which is most of the ₹17,843 crore approved cost.

The partnership was technical too. JICA describes the orthotropic steel deck used on the bridge as “Japan’s bridge technology”, used in India for the first time, and a Japanese firm, IHI, was part of the joint venture that built the longest package. In JICA’s opening-day release, Japan’s ambassador Suzuki Hiroshi called the link “the game changer” for the Mumbai region.

MMRDA dates the start of work to March 2018. The formal start was widely reported as 24 April 2018. The first pier went up at Sewri in May 2019, and in January 2020 the first large precast girder was launched. At the peak, more than 14,000 workers were deployed in round-the-clock shifts.

Much of the Mumbai end was built in the intertidal mudflats off Sewri, where the harbour drains almost dry at low tide. That ruled out ordinary barge work for part of the day and ordinary land work for the rest. The project used reverse circulation drilling for its foundations, a first in India according to project accounts, and large segments were cast on shore and moved into position.

The original schedule assumed completion in about four and a half years, around 2022. The COVID-19 pandemic cost roughly eight months, and the target moved to 2023 and then to the end of that year. JICA later credited the engineers with finishing despite difficulties “including the waves of COVID-19 pandemic”.

Most of Atal Setu is a conventional precast concrete viaduct. Where it crosses navigation channels and sensitive areas it switches to orthotropic steel deck (OSD) spans: a steel plate stiffened underneath by a grid of ribs and cross-beams, so the deck carries load differently in two directions. Because it is much lighter than an equivalent concrete deck, a span can be longer. Longer spans mean fewer piers in the water, which leaves more room for ships and disturbs less of the seabed.

The spans were fabricated abroad, in Japan, Myanmar, Taiwan and Vietnam according to project reports, shipped to Mumbai, assembled into erection units and carried out on a special barge. JICA says the barge had lifting towers fitted with 16 strand jacks of 300 tonnes each, which raised each unit onto its piers.

The first OSD span, in Package 1, was erected on 14 January 2022. It was 118.8 metres long and weighed about 1,331 tonnes. The longest spans on the bridge are 180 metres, at roughly 2,200 to 2,400 tonnes each depending on the source, and Tata Projects says they are the longest steel deck spans in India. Package 2 alone used 32 OSD spans containing about 34,726 tonnes of steel.

The Sewri end of the bridge sits beside the Sewri–Mahul mudflats, where lesser and greater flamingos gather every winter in numbers estimated at 20,000 to 30,000 when the project was being cleared. That is why the 2015 forest clearance was held up, and why the project commissioned studies of the birds before building.

The mitigation measures are specific. MMRDA says the steel-deck design and noise barriers were used to reduce disturbance to flamingos, and street lighting was designed to fall on the carriageway rather than spill onto the water. Compensation was paid to more than 1,500 fishing families whose grounds the construction affected. Whether the flamingos’ numbers are affected in the long term is still a question for monitoring, not something the opening settled.

In June 2023, with about 95% of the work done, the Maharashtra cabinet decided to name the bridge after former prime minister Atal Bihari Vajpayee. MMRDA records construction as complete on 5 January 2024. On 12 January 2024 Narendra Modi inaugurated the Atal Bihari Vajpayee Sewri–Nhava Sheva Atal Setu, built, in the government’s words, at a cost of “more than Rs 17,840 crore”. It opened to traffic the next morning, 13 January. The next day, 14 January, was the busiest single day reported, at about 61,800 vehicles, many of them sightseers.

The rules marked it out from an ordinary city road. The speed limit is 100 km/h. Two-wheelers, auto-rickshaws, tractors and slow-moving vehicles are banned. Tolls are collected by open-road tolling. The one-way toll for a car was set at ₹250, or ₹375 for a same-day return, which is itself a 50% concession on the notified rate. In January 2026 the state extended that concession to 31 December 2026 and exempted electric cars and buses entirely.

In June 2024, the Congress’s Nana Patole showed cracks in the road and called it evidence of corruption. MMRDA replied that the cracks were minor longitudinal cracks in the asphalt of Ramp 5 of the Ulwe approach road, not the bridge structure, and repaired them the same day.

The headline numbers are large. MMRDA reported that 50,04,350 vehicles used the bridge between 13 January and 25 August 2024, including BEST, NMMT and MSRTC Shivneri buses. By the end of 2024 the cumulative count was close to 80 lakh.

The daily numbers tell a different story. In its first year Atal Setu averaged 22,689 vehicles a day, reported Business Standard, against a projection of about 57,525. An RTI reply reported by Moneylife put the gap between projected and actual traffic at close to 70% for one earlier forecast. Reports in 2026 put daily use at around 25,000.

Three causes come up again and again. The toll is steep compared with the Vashi route, which has been toll-free for cars since October 2024. The road links at either end were unfinished: at Sewri, traffic lands in the congested Eastern Freeway area, and at Chirle it still has to find its way to the Mumbai–Pune Expressway. And the demand the bridge was built for had not arrived yet. The Navi Mumbai International Airport, which the bridge was meant to serve, opened only in late 2025. A bridge designed for about 70,000 vehicles a day is, so far, a bridge with spare capacity.

Navi Mumbai International Airport. Inaugurated on 8 October 2025, the airport began commercial flights on 25 December 2025. Atal Setu’s Shivaji Nagar interchange at Ulwe is its fastest road link from South Mumbai. That is the single biggest new source of demand for the bridge.

Sewri–Worli elevated connector. A 4.5 km, four-lane elevated road to carry Atal Setu traffic west to Worli, the Bandra–Worli Sea Link and the Coastal Road. Its foundation stone was laid in February 2021 and it was meant to open with the bridge. The rebuilding of the century-old Elphinstone road bridge over the railway slowed it down. Reports in July 2026 put its opening in early 2027.

Atal Setu–Mumbai–Pune Expressway connector. A 7.35 km, six-lane elevated corridor from Chirle to the expressway near Palaspe. In April 2026 MMRDA reported 143 of 176 foundations, piers at 141 locations, pier caps at 88 and 653 of 830 precast girders done, with completion targeted for February 2027.

The pattern matters beyond Mumbai. Atal Setu did not wait for engineering. India could have built a sea bridge long before 2018. It waited for a financing model that did not depend on tolls covering the whole cost, and an owner with the mandate to justify the bridge by regional growth. Once both existed, the physical work took about six years.