One of India's biggest digital vulnerabilities sits on a six-kilometre stretch of Mumbai's Arabian Sea coast.

Around Versova, a densely populated neighbourhood on the city's northwest, at least 13 of India's 18 intercontinental submarine cables come ashore within six kilometres of one another.

Together they carry as much as 95% of India's international bandwidth to Europe, Africa and West Asia.

"This network faces a critical vulnerability due to severe geographic concentration," says Anwesha Sen of Takshashila Institution, a think tank.

"If several of those cables were cut simultaneously, either accidentally or deliberately, a bulk of India's westward bandwidth to West Asia, Africa and Europe would be impacted."

Cable architecture allows traffic to be rerouted, so a cut would not cause a total blackout.

Traffic could be diverted through other landing points, including the southern cities of Chennai and Kochi, say experts. (India's 18 subsea cables land in Mumbai, Chennai, Cochin, Tuticorin, and Trivandrum.)

But even performance degradation - small increases in the time it takes data to travel - could be costly for banks, stock exchanges, cloud providers and government networks. AI infrastructure may be particularly sensitive because it relies on high-volume, high-speed data transfers.

That vulnerability stems from how much of the world's digital traffic depends on these cables.

At least 13 of India's 18 intercontinental cables land within a six-kilometre stretch at Mumbai's Versova beach

They are the internet's hidden highways - bundles of optical fibres on the ocean floor carrying data between continents as pulses of light. Humans have laid some 870,000 miles (1.4 million km) of them, "lacing the Earth tightly together", writes Samanth Subramanian in his new book The Web Beneath the Waves. These cables carry about 99% of global communication traffic.

Cheap data has helped make India one of the world's biggest internet markets. By late 2025, it had more than a billion broadband subscribers. India's growing digital economy and services sector increasingly depend on these cables.

But India's growing reliance on this invisible infrastructure sits uneasily with how little of it the country actually has.

India accounts for roughly 20% of global consumption of data, but is connected to only about 3% of the world's submarine cables.

It has 21 cable landing stations - coastal gateways where undersea cables connect to terrestrial networks - compared with roughly 1,900 planned and active globally, giving India about 1% of the world's total, according to the Broadband India Forum (BIF).

"We need to grow the number of cable landing stations several fold," says Aruna Sundararajan, chairperson of BIF.

Experts believe this is the paradox at the heart of India's digital transformation: the country is becoming an internet and data-centre powerhouse without controlling enough of the physical infrastructure that connects it to the world.

Technicians work at a western India factory making fibre-optic strands for data centres powering the global AI boom

A recent paper by Takshashila Instituition finds that 11 of India's 18 international cables are more than 20 years old, approaching the nominal 25-year operating life of submarine cable systems.

"It's true that a significant share of India's landing cables are approaching economic end-of-life, and that is a legitimate area of focus," says Amajit Gupta, group CEO and managing director of Lightstorm, a digital infrastructure company.

And then there are cable faults - a far more common risk than deliberate attacks.

Globally, there are an estimated 150-200 cable faults a year, most caused not by saboteurs but by fishing, ship anchors, natural hazards and equipment failure.

"We've seen a version of this scenario play out with the Red Sea disruptions," Gupta said, when traffic was rerouted east through Singapore and onward to the US.

And when an undersea cable breaks, India has another striking weakness: it has no domestic subsea cable-repair ships.

Repair ships have to come from abroad and obtain permission to operate in Indian waters.

"Every cable fault in Indian waters depends on foreign repair ships from Dubai or Singapore. Once a foreign ship is assigned, it must obtain licences to operate in Indian waters, adding weeks to an already lengthy process," says Sen.

That dependence on foreign repair capacity is the more fundamental weakness.

"The bigger structural issue for India isn't rerouting capability - it's repair capacity," says Gupta.

"That combination – dependence on foreign repair capacity and regulatory lead times – represents the real bottleneck," he says.

A high-speed submarine cable linking Singapore to France being installed in southern France

But repair is only one part of the challenge.

Gupta believes the question isn't whether India is retiring old cables, but whether new terrestrial and subsea capacity can keep pace with AI-driven demand. "The industry cannot afford to catch up; it must stay ahead," he says.

That demand is also fuelling a rapid build-out of data centres - the computing hubs where data is stored and AI models are trained and run. They too depend on fast, reliable links to global cloud and internet networks.

Government figures show installed data-centre capacity has risen from 375MW in 2020 to about 1,575MW today.

That creates a potential mismatch.

"Subsea cable planning itself takes three-four years and then cable laying also takes up to two years depending upon cable length," says Sundararajan. "Thus, there can be some lag in getting subsea cable capacity to feed the upcoming data-centre capacity."

The bigger hurdle may be India's bureaucracy.

Sundararajan says 16 agencies across telecoms, defence, home affairs, shipping, ports, environment and state authorities are involved in clearing the construction, operation and repair of subsea cables.

Setting up a cable landing station alone can require around 50 clearances across at least 16 ministries, she says. "A core issue is fragmented governance, not a lack of technical capability."

She wants India's Department of Telecommunications to be the main agency, with a single-window system to speed up repair-vessel permits.

Sundararajan says the government should pre-identify and pre-approve multiple cable landing sites on both coasts and in island territories with standard conditions so cable companies do not have to start the approval process from scratch.

To become a genuine regional cable hub, she says, India needs "predictable regulation, open infrastructure and rapid repair mechanisms" - the kind of environment that has helped Singapore attract cables and data traffic.

Some 870,000 miles of optical fibres on the ocean floors carry about 99% of global communication traffic

Pooja Bhatt, an associate professor at OP Jindal Global University, says that mismatch is increasingly difficult to ignore.

"Given its young demographics and 'Digital India' aspirations, it makes sense for the nation to build and maintain its own internet infrastructure for security and governance purposes," she says.

India has already taken a step: the government now treats submarine cable systems as critical telecommunications infrastructure, recognising their importance to international connectivity.

Sundararajan says the designation should bring faster clearances, emergency repair mechanisms and an Indian cable-repair capability, along with legally protected cable zones around landing sites and routes, restricting anchoring and trawling.

Technology could help too.

A technology called Distributed Acoustic Sensing can turn optical fibres into sensors capable of detecting vibrations from ships, anchors or underwater vehicles – potentially identifying threats before a cable is severed.

But the immediate fixes are possibly more mundane: more landing stations, greater geographical diversity, faster permissions, protected cable routes and an Indian repair capability.

"Connectivity has historically clustered around Mumbai because the ecosystem, infrastructure and demand were already concentrated there," Gupta says. "But that concentration is exactly the risk the industry needs to design away from."

That shift is already beginning.

Four new submarine cable systems are being commissioned, with three more planned. Lightstorm is leading a consortium building one of them, I-2SEA, linking India with Malaysia and Singapore. The system will have dual landings in India – at Machilipatnam, providing a shorter subsea route to Hyderabad, and at a new landing location in South Chennai, adding diversity to existing routes.

For a country consuming data at extraordinary speed, the infrastructure carrying it remains surprisingly fragile. India is adding data centres and preparing for an AI-heavy future. The question is whether its cables, landing stations and repair capacity can keep up.