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Monty Khanna, “A Roadmap for Securing India’s Undersea Cables,” ORF Special Report No. 266, June 2025, Observer Research Foundation.
Undersea cables play a critical role in keeping the economic engines of the world in motion. They are responsible for the carriage of 97 percent of global data traffic and roughly US$10 trillion of international financial transactions daily.[1] For India, the value of its services exports in 2023-24 stood at US$341.11 billion, with the vast majority of it using undersea cables as a conduit for delivery.[2] This reliance is only anticipated to increase, as India’s services exports are projected to rise to US$618 billion by 2030, surpassing its exports in merchandise.[3] Yet, India is currently served by only 17 trans-oceanic cables, the bulk of which land within a six-kilometre stretch of Versova beach, just north of Mumbai—a significant strategic vulnerability.
The laying down and maintenance of the fibre optic (FO) cables that constitute undersea cables is a complicated process. Such cables traverse the oceans, connecting one cable landing station (CLS) on terra firma to another. They are laid by specially designed cable-laying ships, complex platforms containing a large turntable on which several thousand tons of cable are wound. Once one end of a cable is connected to a CLS using a smaller vessel (as the larger cable-laying ships, which displace over 10,000 tons, cannot ply in shallow waters), the ship traverses along a pre-determined route, reeling out the cable while maintaining a certain tension to ensure it is laid straight. In shallower waters, the cable is fed through a trenching device that sits on the seabed, either on skids or tracks, and digs a trench, normally about half a metre to a metre deep, using either a plough or a water jet. As the device moves forward, the cable is placed in the trench, which is simultaneously covered. Such a method is adopted at depths where the cable may be damaged by the anchor of a ship or the trawl of a fishing boat (deep-water seabed trawls today are known to go down to depths of about 1,000 metres). Depending on the probability of such incidents occurring and keeping in mind changes that may occur over the 30-year life of the cable, trenching may be adopted till depths of 2,000 metres. From that point onwards, cables are simply laid out on the seabed.
Insofar as the cable itself is concerned, modern-day undersea FO cables are complex in design. They contain several strands of optical fibre, sometimes bundled into separate groups, each sheathed in a PVC sleeve. These can thereafter be armoured by placing them inside flexible metal jackets woven together using metallic wires. To save costs, armouring is resorted to only in regions where the probability of damage to the cable is assessed to be high. Cables also feature repeater units at set intervals along their length—as the traffic that flows through these cables tends to get attenuated over distance, it needs to be periodically amplified to ensure a high quality of data. These repeaters require power, for which provision is made by running separate cores within the cable itself.
Although the quality of cables has improved over the years, they can still develop defects, either due to external factors such as running afoul of an anchor cable or fishing trawl or technical issues such as the failure of repeater units. In most such cases, the services of specialised cable-repair ships are sought. Often, to effect repairs, the cable has to be lifted out of the water and brought to the deck of the vessel. As there is often inadequate slack in the cable to do so, particularly in deeper waters, the cable needs to be cut using specialised equipment. Once cut, both the ends are lifted to the surface and, turn by turn, attended to for defect identification and repair. On completion, a short new length of FO cable is spliced to both the ends of the cut cable, and once continuity has been established and checked, the cable is lowered back to the seabed.
On 22 March 2025, The South China Morning Post (SCMP) published a report on a compact, deep-sea, cable-cutting device capable of severing the world’s most fortified underwater communication or power lines. The device has been designed to operate with China’s advanced crewed and uncrewed submersibles, like the Fendouzhe, or Striver, and the Haidou series.[4] Expectedly, there has been an outpouring of concern and outrage by several commentators on the subject.
Yet, as the working of undersea cables shows, a plausible reason for the existence of the device could be as legitimate equipment that can be used for the repair of malfunctioning cables. Deep-sea cable cutters of various designs have been in use for decades, and there are perfectly legitimate reasons to develop and improve upon such devices.
That being said, the dual-use nature of such gadgets should be considered, particularly in light of an increase in incidents of cables being disrupted in the Baltic Sea as well as in the vicinity of Taiwan over the past 18 months.[5] The Baltic alone has witnessed at least 11 such incidents over the past 15 months.[6] Attributing all of these incidents to accidents defies the laws of probability.
This report outlines a set of recommendations to mitigate the risk of disruption to undersea cables.
As per Goldman Sachs, 570 subsea cables globally account for more than 90 percent of world data movement.[7] Of these, India hosts just 17 international subsea cables across 16 landing stations, of which at least 11 are nearing the end of their economic life. The total capacity of these cables stood at 193 TBPS at the end of 2024, with an activated capacity of 148 TBPS.[8] With the anticipated commissioning of three new cables this year, i.e., 2Africa Pearls, India-Asia-Express, and India-Europe-Express, India’s internet capacity is expected to grow manifold, thereby significantly improving the speed and reliability of its digital connectivity. However, even this capacity expansion may not be sufficient.
During the First International Subsea Cables System Conference held in New Delhi in March 2025, Anil Kumar Lahoti, chairman of the Telecom Regulatory Authority of India, advocated for a 10x expansion in India’s subsea cable infrastructure to meet surging demand.[9] India, which consumes about 20 percent of global internet traffic, constitutes 2 percent of global subsea traffic, and just 3 percent of global subsea cables land in the country. In contrast, Singapore has 26 subsea cables converging in three landing sites.
While geography might be a factor for this discrepancy, India’s complex regulatory framework contributes to making it an unfavourable destination to set up CLSs. Considering the strategic implications of this imbalance, it needs to be corrected by providing the necessary policy impetus to encourage a greater number of long-distance undersea cables to land in India.
The vast majority of India’s subsea cables land at CLSs in the vicinity of Versova, Maharashtra.[10] The concentration of such critical infrastructure in one area creates a vulnerability that needs to be addressed. This could be done by providing policy incentives to cable-owning and -operating companies, to ensure that as new cables are laid, their landing stations are dispersed across different locations in peninsular India.
In 2023 alone, over 200 submarine cable repairs were reported globally.[11] India currently does not have its own cable repair ship, and cable operators are forced to contract foreign companies to provide such services in the event of an incident. There are reportedly two consortiums that provide such services, one based in Dubai and the other in Singapore. Most Indian operators have signed multi-year contracts with one of these.[12] The problem with this arrangement is that servicing a request for cable repair is subject to vessel availability. Thereafter, there is the tyranny of geography to contend with, as vessels require time to redeploy from one part of the globe to another. Lastly, there is the task of navigating India’s complex regulatory framework, which requires clearances from multiple government agencies and the presence of a government representative on the vessel when repairs are being undertaken. All the above mean that a repair job that essentially takes just a few days to fix takes months to commence.
The presence of a domestically owned and -operated cable repair ship could compress this timeline. Given the intermittent requirement of such a capability, it would be best if government and private industry jointly set up a consortium to acquire and run the vessel/s under a public-private partnership model. While it is understood that such an effort is already underway by the Department of Telecommunications, this effort needs to be expedited. In the interim, a concerted effort needs to be made to ease the regulatory burden for foreign vessels to fulfil this role in a timebound manner.
The Indian Navy will be commissioning two large diving support vessels shortly, each of which displace 9,350 tons.[13] These will be capable vessels with robust saturation diving facilities, dynamic positioning systems, and remotely operated submersibles, along with a moon pool and high-capacity A-frame[14] at the stern to meet all hoisting/lowering requirements. In addition, they will have sufficient empty space on their deck to install containerised modules of various varieties. In short, they will have most of the capabilities required of a vessel to undertake cable repairs. If the Navy were to invest in a few containerised kits to undertake cable repair and train a few core personnel in their use, a domestic repair capacity could be made functional rapidly. This would be of use, particularly in times of conflict when it may be challenging for commercial vessels to undertake this task. Similar parallel efforts could also be initiated by the National Institute of Ocean Technology (NIOT) and the National Institute of Oceanography (NIO) as they go about acquiring research vessels with capabilities for operating submersibles.
Modern-day technological developments allow FO cables to detect vessels in their vicinity. The technique best suited to do so is called distributed acoustic sensing (DAS), which works by sending laser light pulses through one of the fibres in an FO cable. When these pulses encounter vibrations of the fibre (caused by the noise emitted by a vessel nearby), they cause minute changes in the scattered light that is reflected back towards the laser light source. By analysing the changes in the backscattered light, DAS systems can determine the location, intensity, and frequency of the sound or vibration.[15] While the use of such techniques may not prevent untoward incidents involving the damage/severing of cables, it would forewarn commercial as well as government authorities ashore of such actions, with adequate accuracy to allow identification of the vessel responsible using existing maritime domain awareness capabilities complemented by a dedicated surveillance effort, if deemed to be necessary. This could be followed up by formal action against the flag state of the concerned vessel, aided by a comprehensive ‘name and shame’ media campaign. The fielding of such capabilities would act as a strong deterrent against entities intending to engage in such activities.
One of the methods of combatting the submarine threat in Indian waters is to lay greater emphasis on underwater domain awareness (UDA). This requires a network of mobile and static sensors to be placed in various parts of our surrounding waters. As the architecture of these sensors is drawn up, it would be prudent to ensure that the threat to undersea cables is one of the many factors taken into consideration in their placement.
In addition to cable repair, India should aspire to establish a domestic cable-laying capability in due course. Even though this would require a much larger investment, as cable layers are large ships often displacing more than 10,000 tons, and have expensive customised equipment, the economic case will strengthen with time as the demand for such activities increases. This is particularly so, as such vessels are also capable of laying undersea power cables, the requirement for which could ramp up considerably once we start setting up offshore wind farms. Commercial requirements could be complemented by strategic considerations, as cables are also required to power and extract data from UDA sensors. Given the classified nature of their placement, it is imperative that an Indian flagged vessel be used for the task.
Global internet traffic may be reliant on undersea FO cables, but outer space-based internet services are showing early signs of making a dent in this monopoly. A March 2025 report stated that, on average, satellite-based internet services will cost consumers only 53-percent more over the course of 30 years.[16] Once fully reusable spacecraft such as the SpaceX’s ‘Starship’ commence commercial operations, thereby bringing down costs of launch, this differential will diminish. Further, as most such capabilities use ultra-large constellations of Low Earth Orbit (LEO) satellites, the difference in latency and download speeds is narrowing. It would be prudent for India to invest in such capabilities, if for no other reason than to build up resilience in connectivity. Given the enormous expenditure involved in the setting up and operating of such constellations of satellites, the current approach of domestic operators getting into partnerships with companies such as Starlink and OneWeb needs to be encouraged and facilitated.
While India develops redundancies in its global connectivity, the country needs to be prepared for outlier incidents such as the cascading failure of multiple FO cables over a short span of time. With the country’s current capacities, India may reach a point when residual cables are inadequate to meet demand. Under such circumstances, India needs to develop the capability to distinguish critical traffic from the non-critical. In this context, it has been reported that currently, over 50 to 60 percent of traffic transmitted by subsea cables is from OTT platforms and hyperscalers, with the rest being corporate and internet traffic.[17] Systems would, therefore, need to be implemented where non-critical traffic could be identified and constricted in a phased manner to ensure that critical traffic continues to flow and the economic and strategic setback of such an eventuality is minimised.
The international regulatory framework for the protection of undersea cables is weak. The Convention for the Protection of Submarine Telegraph Cables, signed in 1884 and applied to all cables outside the territorial waters of states, requires all states to incorporate its protections into their domestic law. Notably, it does not apply to actions taken by belligerents during war. The provisions of this treaty are incorporated in the United Nations Convention on the Law of the Sea under articles 112 to 115 without any significant changes.
Given the ubiquity and criticality of international data flow today, its assured availability must be seen as a ‘public good’. This intent should be captured by the drafting of a much stronger international regulatory regime. India, being a leader in the use of the internet, could play an important role in the drafting of such a convention.
In conclusion, it may be summarised that given the critical requirement of having assured data connectivity in both peace and conflict, several measures need to be initiated to enhance the resilience of our undersea cable network. These have to be done in a timebound manner with constant monitoring backed by policy intervention and facilitation. Thus, while China may have had its own motivations for announcing to the world the fielding of a new cable-cutting device, it has provided us with an opportunity for a deeper examination of India’s connectivity vulnerabilities. This report aims to provide an impetus to the process of charting out a roadmap to mitigate these vulnerabilities.
[1] Yoni Tobin and VADM Michael J. Connor, USN (ret.), “To Protect Undersea Cables in the Middle East, US Needs a New Hub,” JINSA, April 23, 2025, https://jinsa.org/protect-undersea-cables-in-the-middle-east/
[2] BW Online Bureau, “India’s Exports Hit $778.21 Bn In 2023-24, Up 67% In Decade,” BusinessWorld, February 3, 2025, https://www.businessworld.in/article/indias-exports-hit-77821-bn-in-2023-24-up-67-in-decade-546818
[3] “India’s Services Sector May Outpace Merchandise Exports by 2030, Touch USD 618 Billion: GTRI,” The Economic Times, November 20, 2024,
[4] Stephen Chen, “China Unveils a Powerful Deep-sea Cable Cutter that Could Reset the World Order,” South China Morning Post, March 22, 2025,
[5] There have been several incidents of cables getting severed under questionable circumstances in the recent past. On 22 October 2023, the Chinese-owned container ship Newnew Polar Bear became the focus of the investigation after allegedly damaging an undersea natural gas pipeline and two telecommunications in the Gulf of Finland. On 17 November 2024, underwater internet cables connecting Sweden–Lithuania and Germany–Finland were damaged allegedly by the Chinese-owned bulk carrier Yi Peng 3. On 25 December 2024, Finnish authorities boarded and took control of the Russian oil tanker Eagle S, registered in the Cook Islands, on suspicion of damaging an undersea power cable and three internet lines connecting Finland and Estonia. On 03 Jan 2025, an undersea cable off the north-east coast of Taiwan was damaged, with authorities blaming a Cameroonian-registered cargo ship, the Shunxin-39, as the likely culprit.
[6] Shamim Chowdhury, “At Least 11 Baltic Cables Sabotaged in 15 Months: What to Know,” Newsweek, January 28, 2025, https://www.newsweek.com/least-11-baltic-cables-sabotaged-15-months-what-know-2021972
[7] Karan Mahadik, “TRAI Chief Calls for 10x Expansion of India’s Subsea Cable Infra to Meet Surging Data Demand,” The Indian Express, March 28, 2025,
[8] Kashish Saxena, “Submarine Cables Are Backbone of India’s Digital Future: Trai Chief,” BusinessWorld, March 26, 2025,
[9] Mahadik, “TRAI Chief Calls for 10x Expansion of India’s Subsea Cable Infra to Meet Surging Data Demand”
[10] Aroon Deep, “India Needs More Undersea Cables for Telecom, Internet Traffic, Experts Say,” The Hindu, March 26, 2025,
[11] Kashish Saxena, “Submarine Cables Are Backbone of India’s Digital Future: Trai Chief,” BusinessWorld, March 26, 2025,
[12] This information is based on discussions held by the author with cable operators.
[13] “Indian Navy Launches Two Diving Support Vessels Nistar and Nipun,” Naval Technology, September 22, 2022,
https://www.naval-technology.com/news/indian-navy-diving-support-vessels/?cf-view
[14] A moon pool is an opening in the centre of a ship (so designed) through which remotely operated vessels can be launched and recovered. It can also be used for diving operations. An A-frame is a gantry-like crane at the stern of a ship designed for lowering or hoisting heavy loads over the stern into the water.
[15] Daniel Pyke, “What is Distributed Acoustic Sensing - How Does it Work?,” Sensonic, January 29, 2025, https://www.sensonic.com/en/blog/what-is-distributed-acoustic-sensing-how-does-it-work--3274/
[16] Kelcee Griffis, Bloomberg, “Musk’s Starlink Satellite Internet Costs 53% More Over 30 Years, Maintenance Twice as Expensive,” The Economic Times, March 26, 2025, https://economictimes.indiatimes.com/industry/telecom/telecom-news/musks-starlink-satellite-internet-costs-53-more-over-30-years-maintenance-twice-as-expensive/articleshow/119495914.cms
[17] Mahadik, “TRAI Chief Calls for 10x Expansion of India’s Subsea Cable Infra to Meet Surging Data Demand”
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Rear Admiral Monty Khanna was commissioned into the Indian Navy in Jan 83. He won the `Best Naval Cadet’ award and Midshipman `Sword of Honor’ ...
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