Air Independent Propulsion can transform the operational profile of conventional submarines. Discuss its strategic significance for India in the IOR, and the challenges in indigenising it.

Air Independent Propulsion (AIP) lets a diesel-electric submarine stay submerged far longer because it relies less on atmospheric oxygen. It therefore needs to snorkel less often, which is when it is most easily detected [1]. India's fuel-cell AIP, developed by DRDO-NMRL, reached a milestone with the Energy Module's Setting to Work Phase-2 at L&T Hazira in October 2026 [1]. It promises a real strategic gain, but indigenising it has been slow and difficult.

Strategic Significance in the IOR

• Stealth and survivability: longer underwater endurance helps sea-denial and patrols near IOR chokepoints, and it complements the SSN/SSBN fleet at a lower cost.
• Force multiplier without new hulls: a ₹1,990 crore contract with MDL (Dec 2024) covers building the AIP Plug and integrating it into Kalvari-class boats [2].
• Technology edge: onboard hydrogen generation, which DRDO calls unique among AIP systems. The prototype was proven in endurance and maximum-power modes in 2021 [3].
• Industrial ecosystem: DRDO, L&T and Thermax (private sector) and MDL (DPSU) work together [3][2]. The skills built here can feed P-75(I), six fuel-cell AIP submarines worth over ₹40,000 crore [4].

Challenges in Indigenisation

• Foreign certification: the hull belongs to the French Scorpene design, so Naval Group must certify the AIP integration [5]. An indigenous system still needs foreign approval.
• Chronic delays: the 2023 target of fitting AIP "soon" [5] has moved to integration in early 2027 [1]. The P-75 boats themselves, due by 2017, were completed only in 2025 [6].
• Quality vs quantity: 53% of Navy vessels are over 15 years old [6]. The Standing Committee on Defence noted 15 ageing submarines against a planned 18 [7]. AIP improves each boat but does not add boats.
• Hydrogen safety: fuel-cell systems demand an "exacting safety culture" [1].
• Cost-benefit opacity: Parliament has asked for a comparison of refitting old boats versus buying new ones [7].

In short, AIP turns the Kalvari boats into stealthier assets suited to the IOR, though slow delivery and foreign design dependence weaken that gain. Three steps would help:

• A published boat-by-boat retrofit plan aligned with each boat's scheduled refits.
• Sea-trial results used to guide P-75(I) choices.
• Design rights secured in future contracts.

Together these would make AIP a real example of Aatmanirbhar Bharat in securing India's maritime neighbourhood.