In 2015, a group of investors spent $300 million to build a single undersea cable between New York and London. It was an effort to connect money. This cable, called Hibernia Express, was designed for one purpose only: to be 5 milliseconds faster than any other route across the Atlantic.
Why?
On Wall Street, a single millisecond can mean millions in trading profits. High-frequency trading (HFT) firms, where AI algorithms buy and sell stocks in fractions of a second, were willing to pay $10 million per connection just to use it.
For decades, traders had fought to be closer to stock exchange servers, shaving off nanoseconds of delay. But now, it was a battle fought under the ocean. To tell a long story short, within days of its launch, billions of dollars in trades surged through the Hibernia Express, leaving slower traders in the dust. High-frequency firms, desperate to maintain their edge, scrambled to buy access, while those who couldn’t afford the premium were effectively locked out of the speed race.
The financial world had a new battleground, not the trading floors of Wall Street, but the deep Atlantic seabed. As regulators scrambled to understand the implications, one thing was clear: faster internet was one part of it, but beyond that, milliseconds meant fortunes and power belonged to the fastest.
Fast forward to March 2025.
While nations race for dominance in space, artificial intelligence, and cybersecurity, a more covert battle is brewing deep beneath the ocean, one that could disrupt economies, cripple militaries, and upend global communications. The front line? Submarine cables, the backbone of the world’s internet infrastructure. And the country making the most aggressive moves in this domain is China.
A series of massive barges extending from a Chinese shoreline into the sea, along with an advanced design capable of cutting undersea cables at unprecedented depths, has drawn the attention of defense experts, raising concerns about their possible use in a future Taiwan invasion.
For India, a rising power with increasing digital dependence, safeguarding undersea cables is no longer a technical concern, it’s a national security priority. Recent Chinese developments in deep-sea cable-cutting technologies, coupled with its expanding naval footprint in the Indian Ocean, signal a growing threat. If left unaddressed, a single strategic attack could paralyze India’s financial systems, disrupt military operations, and leave millions disconnected.
What is the strategic importance of submarine cables? What are China’s deep-sea warfare capabilities? India’s vulnerabilities? and the urgent measures New Delhi must take to counteract this looming risk?
Why Submarine Cables Matter
Submarine cables are often overlooked in discussions about critical infrastructure, but their importance cannot be overstated. These fiber-optic networks, stretching over 1.4 million kilometers across the ocean floor, carry more than 95% of global internet traffic, including financial transactions, military communications, and everyday data exchanges.
Why These Cables Are Vital?
- Financial Markets: A vast portion of stock trades, banking transactions, and economic data flows through these cables.
- Military Operations: Encrypted military communications, intelligence sharing, and defense coordination depend on them.
- Civilian Internet and Cloud Services: Almost everything from Google searches to Zoom calls relies on these underwater highways.
India, as one of the fastest-growing digital economies, is highly dependent on undersea connectivity. A single attack on a major cable could cost the nation billions of dollars, disrupt industries, and create panic. This makes their security as important as land borders, airspace, or satellite networks.
China’s Deep-Sea Strategy
China has been rapidly expanding its naval capabilities, but one of its most underestimated advancements is in deep-sea operations. Recent reports indicate that the country is investing in specialized vessels and submersibles capable of severing or tapping undersea cables, a form of ‘gray zone warfare’ that could cripple adversaries without firing a single shot.
Evidence of China’s Intentions
- Mysterious Cable Disruptions Near Taiwan (2023): Taiwanese officials reported that two undersea cables linking the country’s outer islands to the mainland were severed. While official attribution remained unclear, experts pointed toward Chinese-linked fishing and survey vessels.
- Deployment of Cable-Cutting Drones & Submarines: China has been developing remotely operated underwater vehicles (ROVs) and autonomous submersibles capable of deep-sea sabotage.
- Increased Maritime Presence Near India’s Cable Routes: Satellite imagery suggests that Chinese survey ships, often linked to military operations, have been operating near critical Indian Ocean cable routes.
- Landing Barges for Disruptive Operations: China’s expansion of large modular landing barges, potentially for quick cable-interdiction missions, signals a strategic shift toward offensive undersea warfare.
If tensions escalate, Beijing doesn’t need to deploy warships or launch missiles. A few well-planned cable cuts could cripple India’s economy, disrupt military coordination, and create mass confusion, without any immediate military retaliation.
India’s Undersea Weakness
Despite being a maritime power with a strong naval presence, India has limited dedicated mechanisms to protect its undersea infrastructure. Its undersea cables run across some of the most geopolitically contested waters, making them highly vulnerable to disruption.
Indian Vulnerabilities
India’s digital backbone is highly dependent on a handful of undersea cable routes passing through chokepoints like the Malacca Strait, the Andaman Sea, and the Arabian Sea. Any disruption, whether due to natural causes, accidents, or sabotage, could cripple India’s global connectivity, affecting financial transactions, defence communications, and essential services.
- Limited Real-Time Surveillance: Unlike nations such as the US, UK, and Australia, which have dedicated systems to monitor undersea infrastructure, India primarily relies on commercial entities and outdated threat assessments. This lack of real-time oversight makes it vulnerable to covert attacks or accidental damage going undetected until a failure occurs.
- No Dedicated Undersea Cable Defense Force: While the Indian Navy and Coast Guard conduct maritime patrols, there is no specialised unit tasked with securing and monitoring submarine cables. Given the strategic importance of these cables, adversaries could exploit this gap to disrupt India’s digital infrastructure without immediate consequences.
- Slow Response to Sabotage or Tampering: Repairing undersea cables is a complex process that can take weeks or even months, during which India would have to rely on satellite-based backups, which offer only a fraction of the required bandwidth. In a conflict or crisis scenario, this delay could severely impact national security and economic stability.
The Economic Fallout
Think of a quiet morning. You just got out of bed and took your phone in your hands while sipping that first morning coffee. The internet doesn’t seem to connect. You wanted to check on your friends’ social media updates, connect with your family, or text your special someone but nothing seems to work. What a bummer! But then you start your work, and that’s when the nightmare begins.
The hum of India’s financial heart suddenly falls silent. Traders at the National Stock Exchange and Bombay Stock Exchange stare at their screens in disbelief, transactions freeze, prices refuse to update, and panic spreads like wildfire. Across the country, millions reach for their phones to make payments, only to find their banking apps unresponsive. ATMs stop dispensing cash. Businesses come to a standstill as cloud services flicker and fail, leaving critical data stranded in an unreachable void.
Meanwhile, inside naval command centers, encrypted communication lines flicker with static. Coordination between air, land, and sea forces slows, forcing officers to rely on outdated contingency channels. As confusion mounts, the realisation sets in, this isn’t a technical glitch. Somewhere beneath the ocean, severed undersea cables have choked India’s connection to the world. The economy grinds to a halt, digital life is paralyzed, and in a single, calculated strike, an unseen adversary has managed to shake an entire nation.
In 2008, damage to an undersea cable in the Mediterranean slowed internet speeds by 70% across India, the Middle East, and North Africa. A deliberate attack in 2025 could be far worse.
Strengthening Undersea Defences
To counter the growing threat to its undersea infrastructure, India needs a comprehensive strategy that integrates technology, military coordination, and international policy efforts.
- AI-Powered Surveillance: Deploy AI-driven ocean monitoring systems to detect anomalies in undersea cables and potential threats in real time. Use satellite-based geospatial tracking to monitor vessel activity around cable routes, identifying suspicious movements before an incident occurs.
- Stronger Naval Presence: Establish a dedicated submarine cable protection task force within the Indian Navy, equipped with specialized assets for monitoring and securing critical routes. Increase anti-submarine warfare (ASW) patrols in high-risk zones such as the Malacca Strait, the Andaman Sea, and the Arabian Sea to deter hostile interference.
- Global Alliances: Collaborate with QUAD nations (India, US, Japan, Australia) to develop a joint undersea infrastructure protection framework, ensuring collective security for vital cables. Push for international treaties that define cable sabotage as an act of war, deterring state and non-state actors from targeting critical communication lines.
- Backup & Redundancy: Develop high-capacity satellite-based data relays to ensure emergency connectivity in case of disruptions. Expand land-based fiber-optic connections with neighboring countries to create alternative routes, reducing reliance on vulnerable undersea networks.
- Rapid Cable Repair: Invest in indigenous deep-sea cable repair vessels, reducing dependency on foreign firms for maintenance and emergency restoration. Form rapid-response teams capable of repairing damaged cables within days, minimizing economic and strategic disruptions.
With rising geopolitical tensions and growing risks to undersea infrastructure, India must act swiftly to fortify its digital lifelines.
Preparing for the Underwater Battlefield
Modern warfare is no longer just about tanks, missiles, and fighter jets. The ability to sever or control undersea cables is a new form of geopolitical leverage, one that China appears to be preparing for aggressively.
For India, recognizing undersea cables as critical national security assets is not optional; it is a necessity. The sooner India acts, the better prepared it will be to defend against this invisible but potentially devastating mode of warfare.
The battle for dominance beneath the waves has already begun. The question is—is India ready?
