Project 75I — UPSC Notes | Legacy IAS 2026

🔑

What is Project 75(I)?

Definition First · Background · Analogy

📖 Definition (Exam-Ready) Project 75(I) — abbreviated as P-75(I) — is a Ministry of Defence (MoD) acquisition programme for the indigenous construction of six advanced conventional diesel-electric attack submarines equipped with fuel-cell-based Air-Independent Propulsion (AIP) for the Indian Navy. It is the successor to Project 75 (which produced the six Kalvari-class Scorpène submarines) and was conceived as part of India's 30-year submarine building plan approved in 1999.

Core objective: Acquire submarines that can remain submerged for up to 2 weeks (vs 48 hours without AIP), dramatically enhancing stealth, endurance, and combat effectiveness. All six submarines to be built in India under Make in India, with indigenous content rising from 45% (first submarine) to 60% (sixth submarine).

Builder: Mazagon Dock Shipbuilders Limited (MDL), Mumbai, in partnership with Germany's ThyssenKrupp Marine Systems (TKMS) — selected as the sole qualified bidder (January 2025, after L&T-Navantia disqualified).
Estimated cost: ₹90,000–1,00,000 crore (escalated from original ₹43,000 crore)
Design: Based on TKMS Type 214NG/214I (next-generation evolution of Type 214)

🔋 "The Submarine that Charges Its Own Silent Battery" Analogy Imagine a diesel car vs a hybrid car. The diesel car (conventional submarine) burns fuel continuously — must stop at a petrol station (surface to snorkel) every 48 hours. The moment it stops to refuel, it's visible to everyone.

Now imagine a hybrid car with a super-quiet fuel cell (AIP submarine). It drives entirely on silent electricity from a hydrogen fuel cell for 14 days — no engine noise, no exhaust, no refuelling stop. Only then does it need to "snorkel" briefly to recharge. P-75I submarines will be this hybrid — almost undetectable for two weeks at a stretch. That's what makes AIP the single biggest upgrade in conventional submarine design in decades.

💡 In Simple Words P-75I = India building 6 next-gen conventional submarines with AIP (can hide underwater for 2 weeks, not just 2 days). German TKMS design. MDL Mumbai builds them. ~₹90,000-1,00,000 crore. Replaces ageing Sindhughosh class (Russian Kilo). Biggest conventional submarine programme in India's history.

🧠 Memory Trick P-75I = Project 75 (the number, after Scorpène identifier) + India (the suffix showing it's the Indian version, bigger and better)
Key numbers: 6 submarines · 2 weeks submerged (AIP) · 45→60% indigenous · ₹90-100K crore · MDL + TKMS · Type 214NG design · Contract expected March 2026

⚡

AIP Technology — The Heart of P-75(I)

Definition · How It Works · DRDO AIP · Types · Quieter than Nuclear

📖 AIP Theory (Exam-Ready) Air-Independent Propulsion (AIP) is a technology that allows a conventional (non-nuclear) submarine to generate electrical power for propulsion WITHOUT using atmospheric oxygen — meaning the submarine does not need to surface or snorkel to run its diesel generators. Normal diesel-electric submarines must snorkel at periscope depth every 48 hours to suck in atmospheric oxygen for diesel combustion. This snorkelling is detectable by radar, sonar, and aerial surveillance — the moment of greatest vulnerability.

AIP solves this by using an oxygen-fuel reaction that occurs in a sealed, self-contained system onboard — no need for atmospheric air.

Working principle of Fuel-Cell AIP (India's choice for P-75I):

Hydrogen (stored as metal hydride or liquid) + Oxygen (stored as liquid oxygen, LOX) are fed into the fuel cell
Electrochemical reaction (no combustion) produces electricity + water — completely silent
Electricity powers the submarine's electric propulsion motors
No moving parts → no acoustic noise → quieter than nuclear submarines

Endurance with AIP: The AIP module acts as an auxiliary power source alongside the main diesel-electric system. It typically extends submerged endurance from 48 hours to 14+ days at slow patrol speeds (3–5 knots). At higher speeds, only the main battery is used.

Water only — zero emissions, zero noise vs DIESEL- ELECTRIC: Diesel needs atmospheric O₂ Must snorkel every 48 hrs → DETECTABLE AIP = 14 days

Fuel-Cell AIP Working Principle — H₂ + LOX → Silent Electricity → Propulsion | No combustion, no noise, 14 days submerged | Legacy IAS Original (CC0)

Three Types of AIP — Which Does India Use?

AIP Type	How It Works	Pros	Cons	Who Uses It
Stirling Engine	Liquid oxygen + diesel fuel → closed-cycle heat engine → electricity	Well-proven, commercially available; simple	Moving parts = some noise; less efficient than fuel cells	Japan (Sōryū class), Sweden, China (Type 039A)
Fuel Cell (H₂-O₂)	Hydrogen + liquid oxygen → electrochemical reaction → electricity + water	Zero moving parts = quietest AIP; most efficient; zero emissions	Hydrogen storage complex (metal hydride); expensive; requires technology maturity	Germany (Type 212, 214); Spain (S-80); India — DRDO NMRL system; P-75I TKMS design
Closed-Cycle Diesel	Diesel engine run with stored LOX instead of atmospheric air	Simple modification of existing diesel; low cost	Noisy; produces exhaust (CO₂) that must be scrubbed	Some older Soviet designs

⭐ DRDO's Indigenous AIP — Status (Critical Current Affairs) DRDO's AIP System: The Naval Materials Research Laboratory (NMRL) under DRDO has developed an indigenous fuel-cell AIP system using Polymer Electrolyte Membrane (PEM) fuel cell technology. Development partner: Larsen & Toubro (L&T).

Timeline (Updated March 2026):

Energy module (fuel cell stack): Slated to be ready December 2025
Integration as "AIP plug" into a submarine: INS Khanderi (2nd Kalvari-class) to be fitted in 2026–27 (shifted from INS Kalvari due to scheduling)
First AIP-equipped Indian Navy submarine: Expected ready by end-2026 (Business Standard, March 2026)
DRDO and Naval Group (France) signed agreement to safely integrate the AIP module into Kalvari-class submarines

Key issue: L&T-Navantia was disqualified from P-75I partly because their AIP was land-tested only — not sea-proven. DRDO's indigenous AIP also faces the same critique — it must be submarine-trialled before being mandated for P-75I. P-75I will use TKMS's German AIP system, not DRDO's AIP (which will go on Kalvari class as retrofit).

📊

Project 75 vs Project 75(I) — Key Differences

Side-by-Side · Historical Context

Parameter	Project 75 (P-75)	Project 75(I) (P-75I)
Initiated	1997 (concept); contract signed October 2005	1998 (conceptualised); DAC approval January 2019 (3rd attempt)
Number of submarines	6 Kalvari-class (Scorpène)	6 new submarines (Type 214NG/214I design)
Designer/OEM	Naval Group (France) — Scorpène design	ThyssenKrupp Marine Systems (TKMS, Germany) — Type 214NG
Indian builder	Mazagon Dock Limited (MDL), Mumbai	Mazagon Dock Shipbuilders Ltd (MDL), Mumbai
Propulsion	Diesel-electric only (NO AIP)	Diesel-electric + Fuel-cell AIP
Submerged endurance	~48 hours before snorkelling	~14 days continuously
Budget	₹23,000 crore (original)	₹90,000–1,00,000 crore (current estimate; was ₹43,000 crore originally)
Indigenous content	~45–60% (later submarines higher)	45% (sub 1) → 60% (sub 6) mandated
Size	Smaller (Scorpène design, ~1,500t submerged)	Larger (Type 214 class, ~1,800t+)
Completion status	✅ All 6 commissioned (final: INS Vagsheer, Jan 2025)	🔄 Contract negotiation stage; contract expected ~March 2026
Purpose	Replaced first-generation submarines; modernised fleet	Replaces ageing Sindhughosh-class (Russian Kilo, 1980s–90s)

💡 Simple Distinction P-75 = French Scorpène, no AIP, ₹23,000 crore, done. P-75I = German Type 214NG, WITH AIP (2 weeks submerged), ₹90-100K crore, contract near signing. Same builder (MDL). Different country, different technology, 4× the cost.

📍

P-75I — Full Timeline & Current Status

⭐ Most Important Current Affairs · Updated April 2026

1997–1999

India's MoD approved 30-year submarine plan (1999, post-Kargil War) — two parallel production lines of 6 submarines each. P-75I conceptualised as the second line.

2010 & 2014

TWO FAILED ATTEMPTS at moving ahead with P-75I — proposals collapsed due to bureaucratic issues, inadequate planning, and OEM withdrawal (Sweden, France dropped out).

January 2019

Third DAC (Defence Acquisition Council) approval — RFP (Request for Proposal) issued to 5 foreign OEMs. Key mandatory requirement: sea-proven AIP system. Five bidders: Germany (TKMS), France (Naval Group), Russia (Rubin), Spain (Navantia), South Korea (DSME).

2021–2023

Sweden (Saab/Kockums) and France exited. Russia's objections about technical demands. Only two teams remained viable: MDL + TKMS (Germany) and L&T + Navantia (Spain).

January 2025

L&T-Navantia bid DISQUALIFIED — MoD rejected their offer because Navantia's AIP system (for the S-80 Plus class) was demonstrated only with land and onboard testing combined — NOT sea-proven as mandated. MDL-TKMS partnership became the sole qualified bidder.

January 27, 2025

MDL received invitation for first round of commercial negotiations. TKMS's proposed design: Type 214NG (Next Generation) or Type 214I — outer hull shaping similar to Type 212CD. Both German AIP and DRDO's indigenous AIP could potentially be integrated.

July 2025

Official commercial and technical negotiations formally begun between MoD Cost Negotiation Committee (CNC) and MDL-TKMS. Estimated to take ~12 months to complete full negotiations.

January 2026

CNC (Contract Negotiation Committee) completed negotiations — MoD preparing to seek CCS (Cabinet Committee on Security) approval. Design finalised.

March 2026 (Expected)

P-75I contract expected to be signed by end of FY2025–26 (March 2026) — Business Standard (March 6, 2026). First tranche of payment expected simultaneously. Production to begin from Year 3 of contract. First submarine expected mid-2030s.

📌 Cost Escalation — Why ₹43,000 crore became ₹90,000–1,00,000 crore The original P-75I budget was ₹43,000 crore. Key reasons for near-doubling:

Transfer of design and construction expertise: India insisted on full ToT (Transfer of Technology) — not just building submarines but gaining capability to design future ones independently. This commands a massive premium.
Indigenisation of mission-critical systems: Sonar, fire control, combat management — all to be developed/manufactured in India
Pandemic-era inflation: Raw material costs, labour, and supply chain costs in both Europe and India surged post-COVID
Timeline delay cost: 25-year delay from original 1999 conception to 2026 signing = cost escalation due to inflation
AIP technology premium: Fuel-cell AIP adds significant cost per submarine over conventional diesel-electric design

🏭

MDL-TKMS Selection & the Type 214 Design

Why Germany Won · L&T-Navantia Disqualified · Make in India

✅

MDL + TKMS (Selected)

Indian Partner: Mazagon Dock Shipbuilders Limited (MDL) — India's premier submarine builder, built all 6 P-75 Kalvari-class submarines

German Partner: ThyssenKrupp Marine Systems (TKMS, HDW) — world's leading conventional submarine maker. Built Germany's Type 212A/214. Delivered Type 209 to India (Shishumar class, 1980s).

Proposed design: Type 214NG (Next Generation) / Type 214I — a generation beyond the Type 214 currently in service with Greece, South Korea, Portugal. Mirrors outer hull of Type 212CD (Germany's latest). Will incorporate TKMS's fuel-cell AIP (proven at sea on Type 212A)

Historical link: TKMS (then HDW) built India's Shishumar-class submarines (Type 209) at MDL in the 1980s — this is India's second German submarine partnership, 40 years later.

❌

L&T + Navantia (Disqualified, Jan 2025)

Indian Partner: Larsen & Toubro (L&T) — India's largest private engineering company

Spanish Partner: Navantia — Spain's state shipbuilder. Proposed submarine: S-80 Plus class

Why disqualified: MoD's RFP mandated a sea-proven AIP system. Navantia's AIP for its S-80 class had been demonstrated using a combination of land testing + onboard static tests — NOT actual sea trials. India's Navy rejected this as not meeting "sea-proven" criteria.

Irony: Navantia's AIP was otherwise closest to India's specifications — but the "not sea-proven" disqualifier was fatal.

L&T's consolation: L&T is involved in DRDO's indigenous AIP development programme, and is part of Project 77 (indigenous SSN) development.

📖 What is the Type 214 / Type 214NG? The TKMS Type 214 is a German-designed conventional submarine with AIP, developed from the smaller Type 212A. Key features of the standard Type 214 (the base design P-75I will improve upon):

Displacement: ~1,800 tonnes (surfaced)
Length: 65 metres | Crew: 27
Propulsion: MTU diesel engines + Siemens electric + HDW fuel-cell AIP (9 × SAFT fuel cell modules; proven at sea for 2+ weeks)
Speed: 20 knots (submerged); 12 knots (AIP)
Weapons: 8 × 533mm torpedo tubes; can fire Harpoon anti-ship missiles, DM2A4 torpedoes, mines
Used by: Greece (4 boats), South Korea (9 boats, built locally), Portugal (2 boats), Turkey (building)

Type 214NG (India's version): Will be custom-designed for Indian requirements — larger, with Indian weapons (Shyena torpedo, DRDO sonar), Indian combat management system, and integration of DRDO's indigenous AIP as an option for future boats.

🛠

Make in India Angle

All 6 submarines built at MDL Mumbai. Indigenous content: 45% (sub 1) → 60% (sub 6). ToT for design capability — India's goal: be able to design next submarines independently. MSMEs to supply components — thousands of jobs.

🔬

DRDO AIP Integration

P-75I submarines will come with TKMS's German AIP. DRDO's indigenous AIP will first be trialled on Kalvari class (INS Khanderi, 2026-27). If successful, later P-75I boats may be fitted with DRDO AIP — a future Atmanirbhar option.

⏱

Production Timeline

Contract sign ~March 2026. Production begins Year 3 (~2029). First submarine expected mid-2030s. All 6 delivered by late 2030s. India's existing Sindhughosh class will have aged 40–45 years by then — urgency is real.

⚠

Issues & Way Forward — P-75(I)

Structural Issues · Delays · Challenges · Solutions

Key Issues

⚠ Issue 1 — Chronic Delays P-75I was conceptualised in 1998. Contract expected only in 2026 — a 28-year gap from concept to contract. Original P-75 itself was supposed to be complete by 2017 — it finished in 2025. First P-75I submarine will enter service in mid-2030s — the Sindhughosh class submarines will be 40–45 years old by then. India's submarine numbers are critically low during this wait.

⚠ Issue 2 — Two Failed Attempts Before 2019 P-75I proposals were moved in 2010 and 2014 — both failed due to bureaucratic red tape, inadequate planning, OEM withdrawals, and "institutional ad-hocism." Russia complained about technical demands. Sweden and France exited. The same programme took three bites of the DAC to get approved.

⚠ Issue 3 — AIP Credibility Problem India's DRDO AIP has only been land-tested — not submarine-tested. The very reason L&T-Navantia was disqualified (land-proven AIP) applies equally to DRDO's system. DRDO AIP's integration on INS Khanderi (planned 2026-27) is critical to prove its sea-worthiness before it can be included in P-75I specifications.

⚠ Issue 4 — Massive Cost Escalation Original estimate: ₹43,000 crore. Current: ₹90,000–1,00,000 crore — more than doubled. Driven by ToT premium, indigenisation requirements, pandemic inflation, and 25-year delay. Each submarine now costs approximately ₹15,000–16,000 crore — comparable to a surface warship.

⚠ Issue 5 — Technology Transfer Reality India has paid billions in ToT fees across submarine programmes but has not yet acquired the capability to independently design a submarine. P-76 (indigenous design) would be the real test — but it's still a concept. The ToT from P-75I must genuinely transfer design know-how, not just manufacturing steps.

Way Forward

✅ Solution 1 — Fast-Track Contracting Sign P-75I contract (March 2026 target). Simultaneously fast-track P-75 Additional (3 Scorpènes + DRDO AIP) as bridge to maintain fleet numbers. Streamline CCS approval process.

✅ Solution 2 — Submarine DRDO AIP Trial Prioritise INS Khanderi AIP integration (2026-27). If successful, DRDO AIP becomes sea-proven — can then be offered for later P-75I submarines and P-75 Additional, reducing dependence on TKMS AIP.

✅ Solution 3 — Genuine ToT, Not Just Assembly Ensure P-75I ToT transfers complete design capability — CAD files, structural analysis tools, propulsion integration knowledge. India must be able to design P-76 without foreign help. Regular audits of ToT compliance.

✅ Solution 4 — P-76 Indigenous Programme Fast-track L&T + DND-SDG indigenous design programme. Design completion by 2026-27 → first submarine by early 2030s → real Atmanirbhar Bharat in submarine construction.

✅ Solution 5 — MSME Ecosystem Development P-75I will require hundreds of specialised components — sonar transducers, periscope optics, torpedo systems, battery cells. Build India's MSME ecosystem for submarine components now so P-76 and beyond can be truly indigenous.

📜

PYQs & Mains — Project 75(I)

Prelims · Mains Framework

⭐ UPSC Prelims — Project 75I ClassicActual PYQ Pattern

What is "Project 75(I)", sometimes seen in the news?

(a) A plan to indigenously build 75 frigates for the Indian Navy over 30 years
(b) India's programme to develop nuclear-powered ballistic missile submarines under the ATV project
(c) An Indian Navy programme to indigenously construct six advanced conventional diesel-electric submarines equipped with fuel-cell AIP technology ✅
(d) A joint India-Russia programme to build 75 Sukhoi fighter jets under the Make in India initiative

Answer: (c)

P-75(I) = MoD programme for 6 conventional (diesel-electric, NOT nuclear) submarines with fuel-cell AIP. Builder: MDL Mumbai. Partner: TKMS Germany. AIP allows 2 weeks submerged. Indigenous content 45–60%. Cost: ₹90,000–1,00,000 crore. Option (b) = ATV programme (SSBNs like Arihant class) — completely different. Option (a) = frigate programme does not exist. Option (d) = Sukhoi/Russia = wrong.

⭐ UPSC Prelims — AIP TechnologyStatic PYQ

Consider the following statements about Air-Independent Propulsion (AIP) technology:
1. AIP allows conventional submarines to stay submerged for up to 2 weeks without snorkelling.
2. Nuclear submarines are stealthier than AIP submarines because nuclear reactors produce no acoustic noise.
3. Fuel-cell AIP uses hydrogen and liquid oxygen to generate electricity through an electrochemical reaction with no combustion.

(a) 1 and 2 only
(b) 1 and 3 only ✅
(c) 2 and 3 only
(d) 1, 2 and 3

Answer: (b) 1 and 3 only

Statement 1 ✓: AIP submarines (with fuel-cell AIP) can stay submerged for ~14+ days at slow speeds. Without AIP, diesel-electric submarines must snorkel every 48 hours. Correct.
Statement 2 ✗ WRONG: Nuclear submarines are actually NOISIER than AIP submarines. Nuclear reactors have mechanical systems (cooling pumps, steam turbines, condensers) that create detectable acoustic noise. Fuel-cell AIP has ZERO moving parts — completely silent. This is the classic counterintuitive trap.
Statement 3 ✓: Fuel-cell AIP: H₂ + O₂ → electrochemical reaction → electricity + water. No combustion (unlike diesel). No moving parts. Zero emissions. Zero acoustic signature. Correct.

⭐ Expected Mains 2026 — Project 75I & India's Submarine Capability250 Words | 15 Marks

"Project 75(I) is both India's most ambitious naval modernisation programme and its most delayed one. Critically examine the significance, challenges, and way forward."

Significance:
Replaces 40-year-old Sindhughosh (Russian Kilo) class. 6 AIP-SSKs = 2 weeks submerged (vs 48 hrs). MDL-TKMS German Type 214NG design. ₹90-100K crore investment. 45→60% indigenous content. Transfer of design expertise (milestone toward P-76 indigenous design). Atmanirbhar Bharat in submarine building. Fills India's most critical conventional fleet gap. China operates 60+ submarines vs India's ~17.

Timeline of delays:
1998: conceptualised → 2010, 2014: two failed DAC approvals → 2019: third DAC approval, RFP issued → Jan 2025: L&T-Navantia disqualified (AIP not sea-proven) → July 2025: negotiations begin → Jan 2026: CNC complete → March 2026: contract expected. Total: 28 years from concept to contract.

Key challenges:
(1) DRDO AIP land-proven only — must be sea-trialled (INS Khanderi, 2026-27). (2) Cost doubled: ₹43K → ₹90-100K crore. (3) Fleet gap: Sindhughosh class 40+ years old, P-75I first submarine only mid-2030s. (4) OEM attrition — Sweden, France, Russia all dropped out. (5) ToT quality — India must gain design, not just assembly capability. (6) MSME ecosystem underdeveloped for submarine-grade components.

Way forward:
Sign P-75I contract March 2026. Fast-track P-75 Additional (3 Scorpènes + DRDO AIP as bridge). Sea-trial DRDO AIP on Khanderi 2026-27. Accelerate P-76 indigenous design (L&T + DND-SDG). Build MSME ecosystem. Ensure genuine ToT — not just assembly licence.

Conclusion: P-75I is critical but delayed. India must ensure lessons from P-75's 20-year journey are applied — ToT must translate to genuine capability. P-76's success will determine whether India truly graduates from submarine buyer to submarine designer.

🧪

Practice MCQs — Project 75(I)

10 Questions · Click to Attempt

📝 10 MCQs — All Key Traps · Updated to April 2026

Q1. Which partnership was selected for Project 75(I) after the other bidder was disqualified in January 2025?

(a) L&T + Navantia (Spain) — for the S-80 Plus class submarine
(b) Mazagon Dock Shipbuilders Limited (MDL) + ThyssenKrupp Marine Systems (TKMS, Germany) — for the Type 214NG design ✅
(c) Hindustan Shipyard Limited (HSL) + Naval Group (France) — for an updated Scorpène design
(d) Garden Reach Shipbuilders + Rubin (Russia) — for a modified Amur-class submarine

✅ (b) MDL + TKMS (Germany). L&T-Navantia was disqualified in January 2025 because Navantia's AIP for the S-80 Plus was demonstrated using land and onboard static testing — NOT actual sea trials as mandated. MDL-TKMS remained as the sole qualified bidder and was invited for commercial negotiations on January 27, 2025. Proposed design: Type 214NG (Next Generation) / Type 214I. This is India's second German submarine partnership — the first was the Shishumar class (Type 209) built at MDL in the 1980s with TKMS's predecessor HDW.

Q2. Why was the L&T-Navantia bid for P-75I disqualified in January 2025?

(a) L&T lacked the manufacturing infrastructure to build submarines indigenously
(b) Navantia's S-80 Plus submarine was too small to carry India's specified weapons load
(c) Navantia's AIP system had only been demonstrated through land-based and onboard static tests — not at sea on an operational submarine — failing the RFP's "sea-proven AIP" mandatory requirement ✅
(d) Spain's government imposed export restrictions on the Navantia S-80 class for national security reasons

✅ (c). India's RFP mandated a submarine with a "sea-proven AIP system" — meaning the AIP must have been tested and proven on an operational submarine at sea, not just in a land facility or during dockside testing. Navantia's AIP for the S-80 class had undergone 50,000+ hours of testing and was otherwise close to Indian specifications — but the testing was done using a combination of land facility + onboard static tests, NOT actual submarine sea trials. India's Navy judged this as not meeting the "sea-proven" criterion. The irony: DRDO's own indigenous AIP faces the exact same criticism (land-proven only) — it must be sea-trialled on INS Khanderi (2026-27) before being considered sea-proven.

Q3. What is the key operational advantage of AIP submarines over conventional diesel-electric submarines?

(a) AIP submarines can remain submerged for up to 2 weeks without surfacing to snorkel, compared to ~48 hours for conventional submarines — dramatically improving stealth and survivability ✅
(b) AIP submarines can travel at 30+ knots submerged, matching the speed of nuclear submarines
(c) AIP submarines can fire nuclear ballistic missiles, giving them strategic deterrence capability like SSBNs
(d) AIP submarines do not require any crew, using autonomous AI navigation systems

✅ (a). The defining advantage of AIP: conventional submarines must snorkel (raise a mast above water to suck in atmospheric oxygen for diesel generators) approximately every 48 hours. This snorkelling is detectable by radar, sonar, and aerial surveillance. AIP generates electricity without atmospheric oxygen — H₂ + O₂ (stored onboard) react in a fuel cell. This allows 14+ days of complete submersion at patrol speeds (3–5 knots). The tradeoff: AIP is slower than diesel when submerged (AIP used for quiet patrol; main battery used for higher speeds). AIP submarines cannot fire ballistic missiles (option c) — that's SSBNs. Speed of 30+ knots is for nuclear submarines (option b).

Q4. The cost of Project 75(I) escalated from the original estimate of ₹43,000 crore to approximately ₹90,000–1,00,000 crore. The PRIMARY reason for this escalation is:

(a) India added 3 extra submarines to the programme, increasing the total from 3 to 6 boats
(b) The Indian Navy upgraded the requirement from diesel-electric to nuclear propulsion mid-programme
(c) The US imposed sanctions restricting India's access to submarine materials, forcing expensive domestic substitution
(d) Transfer of design and construction expertise (genuine ToT), indigenisation mandates, post-pandemic cost inflation in Europe and India, and 25+ year delay since original conception ✅

✅ (d). Multiple factors caused the cost doubling: (1) Genuine ToT premium — India insisted TKMS transfer complete design and construction expertise (not just licence to build), which commands a massive premium. (2) Indigenisation requirements — 45–60% Indian content forces development of local supply chains at higher initial cost. (3) Pandemic inflation — European and Indian material/labour costs surged post-COVID. (4) 25-year delay since 1998 conception — inflationary impact over two decades. The programme was NOT extended from 3 to 6 submarines (option a). There was no mid-programme switch to nuclear propulsion (option b). No US sanctions specifically affected this programme (option c).

Q5. What is the difference between Project 75 and Project 75(I)?

(a) P-75 built nuclear submarines; P-75I builds conventional submarines
(b) P-75 built 6 French Scorpène-class diesel-electric submarines WITHOUT AIP (₹23,000 crore, completed Jan 2025); P-75I will build 6 German Type 214NG submarines WITH fuel-cell AIP (₹90-100K crore, contract ~March 2026) ✅
(c) P-75 was built at Garden Reach Shipbuilders; P-75I will be built at Mazagon Dock
(d) P-75 used Russian Kilo-class technology; P-75I uses French Scorpène technology with improved sensors

✅ (b). P-75 = French Scorpène (Naval Group) design, built at MDL Mumbai, no AIP, ₹23,000 crore, all 6 commissioned (INS Vagsheer = final, Jan 2025). P-75I = German Type 214NG (TKMS) design, built at MDL Mumbai, WITH fuel-cell AIP (2 weeks submerged), ₹90-100K crore, contract expected March 2026. Both built at MDL — not Garden Reach (option c). Russian Kilo = Sindhughosh class — P-75I replaces these (option d). Both P-75 and P-75I are conventional (non-nuclear) submarines (option a).

Q6. DRDO's indigenous AIP system (developed by NMRL) will be FIRST trialled on which submarine?

(a) INS Vagsheer (S26) — the 6th and newest Kalvari-class submarine
(b) The first P-75I submarine being built at MDL Mumbai
(c) INS Khanderi (S22) — the 2nd Kalvari-class submarine, during its scheduled refit in 2026-27 ✅
(d) INS Sindhuratna — the oldest Sindhughosh-class submarine still in service

✅ (c) INS Khanderi (2026-27). The DRDO AIP module (energy module = fuel cell stack) was slated to be ready by December 2025 (L&T as development-cum-production partner). The plan shifted from originally fitting INS Kalvari (1st submarine) to INS Khanderi (2nd submarine) due to scheduling. INS Khanderi will receive the AIP "plug" during its refit in 2026-27. If successful, this makes DRDO's AIP "sea-proven" — critical because: (1) It can then be considered for P-75 Additional (3 new Scorpènes) and (2) It strengthens India's bargaining position with TKMS for later P-75I boats. Until sea-trialled on Khanderi, DRDO AIP faces the same criticism that disqualified Navantia.

Q7. Project 76 (P-76) is India's most ambitious submarine initiative because:

(a) It will build nuclear-powered attack submarines (SSNs) — India's first indigenous SSN programme
(b) It will build 76 conventional submarines to match China's underwater capability
(c) It is a joint India-USA programme to build Virginia-class submarines in India
(d) It aims to build fully indigenous conventional submarines (SSK) designed entirely in India by L&T and the Navy's DND-SDG — without any foreign OEM — India's first true Atmanirbhar submarine design ✅

✅ (d). Project 76 = India's attempt to design and build a submarine completely indigenously — no Navantia, no TKMS, no Naval Group. Partners: L&T (private sector) + Indian Navy's Directorate of Naval Design, Submarine Design Group (DND-SDG). 6 submarines planned. Design phase: 2026-27. First submarine: ~6-7 years after design. India's indigenous SSN programme = Project 77 (option a — different from P-76 which is conventional). P-76 has nothing to do with USA or Virginia-class (option c). The "76" number is a sequential identifier — not "76 submarines" (option b).

Q8. What is the "P-75 Additional" programme and why is it strategically important?

(a) It adds 75 new frigates and destroyers to the Indian Navy to escort the P-75I submarines
(b) It procures 3 more Scorpène-class submarines (from Naval Group + MDL) with DRDO AIP — bridging the fleet gap while P-75I's long construction period plays out ✅
(c) It upgrades all existing 6 Kalvari-class submarines with nuclear propulsion retrofitting
(d) It is an additional order of 75 AIP modules from Germany for the P-75I programme

✅ (b). P-75 Additional = 3 more Scorpènes (same French design as Kalvari class, slightly larger) from Naval Group + MDL at ~₹36,000 crore. These are a "bridge" because: P-75I's first submarine won't arrive until mid-2030s, but India's Sindhughosh class submarines (1980s-90s Russian) are rapidly ageing out. The 3 additional Scorpènes can be built quickly (MDL already has the production line, supply chain, and expertise) and will carry DRDO's indigenous AIP — making them both a stopgap AND a proving ground for Indian AIP technology. Strategic benefit: keeps India's conventional submarine fleet numbers from collapsing in the late 2020s-early 2030s while P-75I is being built.

Q9. The 30-year submarine building plan approved by India's CCS in 1999 (post-Kargil War) called for how many submarines in total?

(a) 12 submarines — 6 conventional + 6 nuclear
(b) 18 submarines — 6 SSK + 6 SSN + 6 SSBN
(c) 24 submarines — two parallel production lines of 12 each (though only 6+6 were authorized initially) ✅
(d) 36 submarines — matching China's submarine fleet at that time

✅ (c) 24 submarines. The 1999 CCS-approved 30-year submarine building plan (to conclude by 2030) called for acquiring 24 submarines — through two parallel production lines, each of 12 submarines. In practice, due to financial constraints and delays, only 6 submarines were authorised for each line: P-75 (6 Scorpènes, done) and P-75I (6 Type 214NG, in progress). The plan was conceived after the Kargil War highlighted India's defence capability gaps. The entire 24-submarine plan was supposed to be complete by 2030 — in reality, P-75I's first submarine won't arrive until mid-2030s, and the 24-submarine target remains far from achievement.

Q10. India insists on "minimum 45% indigenisation, rising to 60% in the 6th submarine" in P-75I. Why is this requirement strategically important?

(a) Builds India's domestic submarine manufacturing ecosystem (MDL, MSMEs, DRDO labs), reduces long-term import dependency for maintenance/spares, generates employment, and develops the industrial base for eventual fully-indigenous submarines (P-76) ✅
(b) Saves money since Indian-made components are always cheaper than imported equivalents
(c) Prevents foreign countries from accessing India's submarine technology through supply chain analysis
(d) Satisfies WTO regulations requiring developing countries to maintain a minimum 45% domestic content in defence procurement

✅ (a). The indigenisation requirement is about building a long-term industrial ecosystem, not just saving money (option b — in fact, indigenisation often COSTS more initially). Benefits: (1) MDL develops deeper submarine construction expertise. (2) Thousands of MSMEs develop submarine-grade components — creating a supply base for future programmes. (3) Reduces dependence on TKMS for spares and maintenance — crucial for operational availability during conflict. (4) Builds the technical workforce and industrial base needed for P-76 (fully indigenous). (5) Aligns with Atmanirbhar Bharat's defence industrial policy. No WTO requirement mandates 45% local content for defence (option d). The concern about foreign access (option c) is addressed through technology security protocols, not indigenisation percentages.

⚡ Quick Revision — All Facts for the Exam

Topic	Exam-Ready Facts
P-75I — What	6 conventional diesel-electric submarines WITH fuel-cell AIP. 2 weeks submerged. MDL (Mumbai) builder. TKMS Germany partner. Type 214NG design. ₹90,000–1,00,000 crore. Replaces Sindhughosh class (Russian Kilo).
AIP Technology	H₂ + O₂ (stored onboard) → electrochemical reaction → electricity. NO combustion, NO moving parts, NO noise. 14+ days submerged vs 48 hrs (diesel-electric). AIP submarines quieter than nuclear submarines.
Status (April 2026)	CNC negotiations complete (Jan 2026). CCS approval pending. Contract expected March 2026. Production starts Year 3. First submarine mid-2030s. L&T-Navantia disqualified Jan 2025 (AIP not sea-proven).
DRDO AIP	NMRL + L&T development. Fuel-cell type. Energy module ready Dec 2025. INS Khanderi to be fitted 2026-27 (first sea trial). P-75I will use TKMS German AIP; DRDO AIP = for Kalvari class and future P-75 Additional.
P-75 Additional	3 more Scorpènes (Naval Group + MDL). ~₹36,000 crore. WITH DRDO AIP. 60% indigenous. Bridge while P-75I is built. Contract ~2026.
P-76	Fully indigenous conventional SSK. L&T + Navy's DND-SDG. Design 2026-27. First submarine ~6-7 years. India's first true Atmanirbhar submarine. No foreign OEM.
P-75 vs P-75I	P-75: French Scorpène, no AIP, ₹23K cr, DONE (Jan 2025). P-75I: German Type 214NG, AIP, ₹90-100K cr, contract ~March 2026.
Delays	1998 conceived → 2010, 2014 failed → 2019 approved → Jan 2025 sole bidder → Jan 2026 CNC complete → March 2026 contract = 28 years from concept to contract
1999 Plan	Post-Kargil CCS approval for 24 submarines over 30 years (2 parallel lines of 12). In practice, only 6 + 6 (P-75 + P-75I) authorised so far.

🚨 5 UPSC Traps — Never Get These Wrong:

Trap 1 — "P-75I = nuclear submarines" → WRONG! P-75I = conventional diesel-electric + AIP. NOT nuclear. Nuclear submarines = SSN (Chakra, Project 77) and SSBN (Arihant class = ATV programme). Completely separate programmes.

Trap 2 — "AIP submarines are noisier than nuclear" → WRONG! AIP fuel cells = zero moving parts = quietest propulsion. Nuclear submarines are noisier (cooling pumps, turbines). AIP > nuclear in stealth terms. This is tested EVERY year.

Trap 3 — "P-75I submarines use French Scorpène design" → WRONG! P-75I = German Type 214NG (TKMS). French Scorpène = P-75 (completed, Kalvari class). P-75I is a different programme, different country, different design.

Trap 4 — "L&T-Navantia won the P-75I contract" → WRONG! L&T-Navantia was disqualified in January 2025 (AIP not sea-proven). MDL-TKMS = sole qualified bidder. Contract expected March 2026.

Trap 5 — "P-75I includes DRDO indigenous AIP" → NOT ACCURATE! P-75I submarines will use TKMS's German AIP system. DRDO's indigenous AIP will be fitted on Kalvari-class submarines (P-75 Additional). DRDO AIP must first be sea-trialled on INS Khanderi (2026-27) to be considered sea-proven.

Project 75I – UPSC Notes

🌊 Project 75(I) — India's Next Submarines

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