Under the leadership of Prime Minister Narendra Modi, India has embarked on a determined course to enhance its maritime security and assert its presence in the increasingly contested Indian Ocean Region (IOR). Recognising the shifting dynamics brought on by China’s expanding naval footprint and Pakistan’s rapid submarine modernisation, the Modi government has prioritised undersea warfare as a cornerstone of India’s naval doctrine. This strategic focus has culminated in ambitious initiatives, such as Project 75I, aimed at equipping the Indian Navy with cutting-edge diesel-electric submarines equipped with Air Independent Propulsion (AIP). These efforts reflect Modi’s broader vision of a self-reliant, technologically advanced defence posture, designed to ensure India’s dominance beneath the waves, protect its critical sea lanes, and maintain regional stability amid rising maritime competition.
India Is Quietly Rewriting Undersea Warfare… Project 75I Explained 🇮🇳🔥
> China is expanding its naval footprint across the Indian Ocean.
> Pakistan’s Navy is being rapidly modernized with Chinese tech.
> Gwadar has replaced Karachi as Pakistan’s new strategic hub.
> Chinese… https://t.co/Fuh9P0gNAR pic.twitter.com/NqebJcyskv— The Tathya (@_TheTathya) January 14, 2026
Why Undersea Warfare Matters
China’s expanding Indian Ocean footprint
Over the past decade, China has steadily expanded its naval activity in the Indian Ocean, reflecting a clear shift toward sustained power projection in the region. This expansion includes regular deployments of People’s Liberation Army Navy (PLAN) submarines and surface combatants, the establishment of dual-use port access agreements across the Indian Ocean Region (IOR), and the operation of intelligence-gathering vessels near Indian waters. These maritime efforts are closely integrated with China’s Belt and Road Initiative (BRI), blending economic infrastructure development with strategic military access. Notably, Chinese submarines have already conducted patrols in both the Arabian Sea and the Bay of Bengal, signaling Beijing’s intent to normalize an undersea presence in India’s primary maritime theater and reshape the regional security environment.
Pakistan’s submarine modernisation
Pakistan’s Navy is undergoing a significant transformation, primarily through Chinese assistance. The induction of advanced Chinese submarines and the strategic elevation of Gwadar as a naval hub have reshaped Pakistan’s maritime posture. Gwadar’s proximity to critical Sea Lines of Communication (SLOCs) gives Pakistan and China enhanced monitoring and interdiction potential in the northern Arabian Sea. Together, these developments pose a multidimensional undersea challenge to India—one that surface fleets alone cannot counter.
India’s Doctrinal Shift: From surface power to silent control
India’s naval leadership has steadily shifted its focus away from symbolic power projection toward a doctrine centered on sea denial, deterrence, and sustained underwater presence. In an increasingly contested maritime environment, submarines, especially advanced conventional platforms, have emerged as the backbone of this strategy. Their ability to operate undetected for extended periods allows India to monitor adversary movements without revealing its own positions, creating uncertainty and caution in enemy planning. By forcing opponents to divert significant resources toward anti-submarine warfare, submarines complicate force allocation and raise the cost of hostile operations.
At the same time, they provide India with credible deterrence and second-strike options, strengthening strategic stability without escalating tensions. Importantly, conventional submarines offer these advantages at a fraction of the cost of nuclear-powered fleets, making them a highly effective and sustainable choice. Project 75I directly embodies this doctrinal evolution, translating India’s strategic priorities into a concrete capability designed for quiet control of the undersea domain.
Project 75I
Project 75I aims to induct six next-generation diesel-electric attack submarines into the Indian Navy. These submarines are intended to complement India’s existing Kalvari-class (Scorpene) boats and bridge capability gaps until a larger nuclear submarine force matures.
Key Objectives
· Long-duration submerged operations
· Extremely low acoustic signatures
· Advanced weapons and sensor integration
· Indigenous manufacturing with technology transfer
· Future upgradeability
Air Independent Propulsion
Traditional diesel-electric submarines face significant operational limitations due to their reliance on batteries that need frequent recharging by running diesel engines. This recharging process necessitates surfacing or snorkeling, which inherently increases the risk of detection. When a submarine surfaces or uses a snorkel, it becomes vulnerable to observation and tracking by maritime patrol aircraft, satellites, and radar and electronic surveillance systems. In the context of modern naval warfare, such detection is extremely dangerous because it typically precedes targeting and destruction, compromising the submarine’s stealth advantage and mission effectiveness.
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AIP Advantage
Air Independent Propulsion allows submarines to generate power without atmospheric oxygen. This enables:
· Continuous submerged operations for weeks
· Drastically reduced acoustic and thermal signatures
· Increased survivability in contested waters
For undersea warfare, AIP shifts the balance decisively toward the defender.
Platform Selection: Why Germany’s Type-214
India’s decision to favour Germany’s Type-214 submarine design reflects a risk-aware and capability-driven approach.
The Type-214 submarine is widely regarded as one of the stealthiest conventional submarines currently in service. It features a proven fuel-cell-based Air Independent Propulsion system that significantly enhances underwater endurance, combined with extremely low noise levels that make it difficult to detect. Its advanced hydrodynamic design further reduces acoustic signatures, while a modular architecture allows for easy upgrades to weapons and sensor systems, ensuring adaptability to future technological advancements. Compared to alternative French and Spanish submarine designs, the Type-214 presents a lower integration risk and benefits from a more mature operational track record, providing greater assurance of performance and reliability.
Additionally, Germany’s extensive experience in submarine technology and its commitment to structured technology transfer make it a trusted and dependable partner for sensitive defense programs like Project 75I.
All six submarines under Project 75I will be built at Mazagon Dock Shipbuilders Limited (MDL) in Mumbai.
Project 75I may not significantly expand the numerical size of India’s submarine fleet, but it will substantially enhance its overall capability and strategic impact. The introduction of these advanced, stealthy submarines will compel adversaries to devote greater resources to anti-submarine warfare (ASW), stretching their operational capacities and raising the cost of hostile activities. By increasing uncertainty and elevating the risk for enemy naval forces, Project 75I will strengthen India’s position in critical maritime chokepoints, including the approaches to the Arabian Sea, the Malacca Strait and its linked sea lanes, and key transit routes through the Bay of Bengal. In undersea warfare, uncertainty itself is a form of power; a silent, undetected submarine exerts influence by shaping adversary behavior and strategic calculations without ever firing a shot.
Project 75I marks a profound transformation in India’s maritime thinking. It reflects an understanding that modern naval power is not defined by what is seen, but by what remains hidden. In a region where adversaries are expanding quietly and persistently, India’s response is equally measured, but far more lethal.
(Tweet-based story)
