- Why in news
- On 13 July 2026, PIB explained three indigenous naval classes (Nilgiri, Sandhayak, Arnala) after INS Dunagiri, Sanshodhak and Agray were commissioned on 21 June 2026 and INS Mahendragiri on 11 July 2026.
- What it is
- The Nilgiri class is the Navy's Project 17A stealth guided-missile frigate class. The Sandhayak class is a set of large survey vessels for hydrography. The Arnala class is a set of shallow-water anti-submarine craft for coastal waters. All three were designed in India and built in Indian yards.
- Project 17A
- A programme to build seven stealth guided-missile frigates, the Nilgiri class, for anti-air, anti-surface and anti-submarine roles.
- Builders of Nilgiri class
- Mazagon Dock built four ships and GRSE Kolkata is building three.
- Sandhayak class
- Four large survey vessels built by GRSE; INS Sanshodhak is the fourth and final ship. They map the seabed and produce nautical charts.
- Arnala class
- Eight-ship class of anti-submarine warfare shallow water craft, built by GRSE with L&T Shipbuilding, replacing the Abhay-class corvettes. A parallel Mahe class at Cochin Shipyard raises planned strength to 16.
- Earlier stealth classes
- Shivalik class (Project 17) was India's first indigenously designed stealth frigate, built at Mazagon Dock; the Talwar class was Russian-built.
Don’t confuse with Shivalik vs Nilgiri class: Shivalik is Project 17; Nilgiri is the follow-on Project 17A with better sensors, weapons and more indigenous content.
Don’t confuse with Arnala vs Mahe class: Arnala-class craft are built by GRSE with L&T; the Mahe class is being built at Cochin Shipyard.
Defence: Prelims tests exercises (with whom), equipment (who makes it) and firsts.
Why it matters
- Layered fleet of surface combat, survey and coastal anti-submarine ships strengthens maritime security in the Indian Ocean Region.
- Serial indigenous production deepens defence manufacturing, jobs and the shift from a Buyer's Navy to a Builder's Navy.
Problems
- Indigenous content is about 75 per cent for Project 17A, so some critical systems are still imported.
Way forward
- Raise indigenous content in sensors and propulsion while keeping delivery timelines.
Put in your answer
Defence exports: Defence exports reached a record Rs 23,622 crore in 2024-25, against Rs 21,083 crore in 2023-24.
Hydrography output: Indian hydrographers surveyed 89,000 sq km and produced 96 charts in 2019-24.
- 2025Mains GS3 · Q20Why maritime security protects sea trade; challenges, way forward.
- 2022Mains GS3 · Q10Maritime security challenges in India and initiatives to improve them.
UPSC’s own questions that come close to this issue, from our Prelims and Mains banks.
No practice question for this one; the card may still help an answer. Why: Defence hardware is asked in Prelims (8 of 327 news-linked questions) but almost never reaches Mains. Worth a card for ship class and project names.
Worth revising until Prelims 2028: most news questions come within two years of the event.