Pakistani corvette collides with Indian warship; India cites the 1991 military pact
Two navies were meant to stay three nautical miles apart. What happens when a 35-year-old safety rule is broken?
Published 17 September 2026. Written by Pratidin from the reports linked at the end; every fact checked by a separate review before publishing. How we work
A Pakistan Navy corvette, PNS Hunain, collided with an Indian Navy warship in the North Arabian Sea, The Hindu reported on 17 September 2026. India said the collision was caused by PNS Hunain's "unsafe and unprofessional" manoeuvring at high speed in international waters. The Indian ship, which was on routine surveillance, suffered minor damage and continued its mission. PNS Hunain was damaged and returned to harbour. No casualties were reported on either side. India lodged a diplomatic protest and summoned Pakistan's Chargé d'affaires. Pakistan in turn summoned India's Chargé d'affaires, called the incident "highly provocative" and said it took place inside Pakistan's Exclusive Economic Zone (EEZ).
India's protest rests on Article 10 of the Agreement between India and Pakistan on Advance Notice on Military Exercises, Manoeuvres and Troop Movements, signed on 6 April 1991. Article 10 requires naval ships and submarines of the two countries to keep at least three nautical miles (about 5.56 km) from each other in international waters. The agreement is a confidence-building measure (CBM): a step that reduces the risk of a crisis caused by misreading the other side's military intentions. It grew out of the alarm caused by India's Exercise Brasstacks in 1986-87, and it requires advance notice of major exercises and troop movements near the border. A similar incident took place in June 2011 between Pakistan's PNS Babur and India's frigate INS Godavari.
The two sides describe the location differently: India says international waters, Pakistan says its EEZ. Under the UN Convention on the Law of the Sea (UNCLOS), an EEZ can extend up to 200 nautical miles from the coast, and the coastal state gets sovereign rights over resources there, but it is not territorial sea, and other states keep freedom of navigation in it. PNS Hunain (pennant F-273) is a Yarmook-class ship built by Damen in Galați, Romania, and commissioned on 26 July 2024. For India, the episode tests whether old India-Pakistan CBMs still work at sea, where warships of both navies now operate close to each other more often.
Prelims facts
- PNS Hunain, a Pakistan Navy corvette, collided with an Indian Navy warship in the North Arabian Sea; India called the manoeuvre "unsafe and unprofessional".
- Article 10 of the India-Pakistan agreement of 6 April 1991 requires warships and submarines of both sides to stay at least three nautical miles apart in international waters.
- The 1991 Agreement on Advance Notice on Military Exercises, Manoeuvres and Troop Movements is a confidence-building measure that followed Exercise Brasstacks (1986-87).
- Pakistan claims the collision took place in its EEZ; under UNCLOS an EEZ extends up to 200 nautical miles and other states keep freedom of navigation there.
- A similar incident occurred in June 2011 between PNS Babur and INS Godavari.
Quick recall
- Which Pakistan Navy ship collided with an Indian warship in September 2026?
- PNS Hunain (F-273), a Yarmook-class corvette
- Where did the collision take place?
- In the North Arabian Sea
- Which article of the 1991 agreement did India cite?
- Article 10
- What distance does Article 10 require between Indian and Pakistani warships?
- At least three nautical miles (about 5.56 km) in international waters
- When was the agreement on advance notice of military exercises signed?
- 6 April 1991
- Which Indian exercise of 1986-87 led to the 1991 agreement?
- Exercise Brasstacks
- Which earlier incident involved PNS Babur and INS Godavari?
- A similar incident at sea in June 2011
- How far can an EEZ extend under UNCLOS?
- Up to 200 nautical miles from the baseline
Prelims practice question
With reference to the India-Pakistan Agreement on Advance Notice on Military Exercises, Manoeuvres and Troop Movements, consider the following statements:
1. It was signed in 1991.
2. It requires naval ships of the two countries to keep a minimum distance from each other in international waters.
3. It was the first India-Pakistan agreement to ban attacks on each other's nuclear installations.
Which of the statements given above are correct?
- 1 and 2 only
- 2 and 3 only
- 1 and 3 only
- 1, 2 and 3
Show answer
Answer: (a) 1 and 2 only. Statement 1 is correct: it was signed on 6 April 1991. Statement 2 is correct: Article 10 sets a minimum distance of three nautical miles between naval ships and submarines in international waters. Statement 3 is incorrect: the ban on attacks against nuclear installations is a separate agreement of 1988.
Asked before in UPSC
Recurring theme: India-Pakistan relations and maritime security: confidence-building measures and the law of the sea
India's approach to maritime security in the Indian Ocean rests on predictable conduct at sea; the collision shows why rules such as Article 10 of the 1991 agreement matter alongside SAGAR and domain awareness.
The Arabian Sea is where India's maritime security concerns concentrate; the 2026 collision adds state-to-state naval friction to the piracy concerns this question discusses.
Mains practice question
India-Pakistan confidence-building measures were designed for land borders and airspace, but incidents at sea are testing them. Examine the relevance of the 1991 agreement on military exercises in the light of the recent naval collision in the Arabian Sea. (150 words)
Model answer
The collision between PNS Hunain and an Indian Navy warship in the North Arabian Sea, which India called "unsafe and unprofessional", has put the 1991 India-Pakistan agreement on military exercises back in focus.
What the agreement provides
- Signed on 6 April 1991 after the scare caused by Exercise Brasstacks (1986-87).
- Advance notice of major exercises and troop movements near the border.
- Article 10: naval ships and submarines to keep at least three nautical miles apart in international waters.
Why it remains relevant
- It gives a legal yardstick: India's protest cites Article 10, not just general norms.
- Repeated incidents (PNS Babur and INS Godavari, June 2011) show the need.
Limits
- The 2026 breach was taken up only through diplomatic protests and the summoning of envoys.
- Rival readings of location: Pakistan says its EEZ, India says international waters.
Way forward
- A dedicated incidents-at-sea arrangement and a working naval hotline.
Reviving and updating CBMs at sea would keep an accident from becoming a conflict.
The basics
Why this matters
India and Pakistan have fought wars and faced repeated crises, yet they have also signed a set of small, practical agreements meant to stop accidents and misunderstandings from escalating. When a Pakistani corvette collided with an Indian warship in the North Arabian Sea, India's protest cited one of those agreements.
Confidence-building measures
A confidence-building measure (CBM) is an arrangement that makes military behaviour predictable. It does not settle disputes. It reduces the chance that one side misreads the other's routine activity as preparation for attack. The India-Pakistan confidence-building measures include notice of exercises, rules on keeping aircraft away from the border, and a pact not to attack each other's nuclear installations.
- 1986-87India's Exercise Brasstacks alarms Pakistan
- 1988Agreement not to attack each other's nuclear installations
- 6 April 1991Agreements on advance notice of military exercises and on preventing airspace violations
- June 2011Incident between PNS Babur and INS Godavari
- 26 July 2024PNS Hunain commissioned into the Pakistan Navy
- September 2026PNS Hunain collides with an Indian Navy warship in the North Arabian Sea
The 1991 agreement
The 1991 India-Pakistan Agreement on Advance Notice of Military Exercises was a direct response to Exercise Brasstacks (1986-87), a large Indian exercise near the border that Pakistan saw as threatening. The agreement asks each side to give advance notice of major exercises and troop movements. At sea, its key rule is Article 10.
- 1Define a major naval exerciseThe agreement uses a threshold of six or more destroyer or frigate-sized ships
- 2Give advance noticeEach side informs the other of major exercises so they are not mistaken for an attack
- 3Keep distanceArticle 10: naval ships and submarines stay at least three nautical miles apart in international waters
- 4Protest a breachA violation is taken up through diplomatic channels, as India did in September 2026
Zones of the sea
The UN Convention on the Law of the Sea (UNCLOS) measures zones from the baseline along the coast. The territorial sea (up to 12 nautical miles) is under the coastal state's sovereignty. The Exclusive Economic Zone under UNCLOS (up to 200 nautical miles) gives the coastal state rights over fish, oil and other resources, but ships of other states may still navigate there. This is why Pakistan's claim that the collision was in its EEZ does not by itself make the Indian ship's presence unlawful.
Go deeper
In one line: A Pakistan Navy corvette, PNS Hunain, collided with an Indian Navy warship in the North Arabian Sea, and India protested that Pakistan broke the three-nautical-mile rule of a 1991 bilateral agreement.
Why it matters for UPSC
India-Pakistan relations, maritime security and the law of the sea are regular Mains themes in GS2 and GS3. Prelims asks about specific agreements, dates and maritime zones. This incident links all three.
The core idea
Two rivals with nuclear weapons need rules that stop accidents from becoming crises. The India-Pakistan confidence-building measures provide such rules. The most relevant here is the 1991 India-Pakistan Agreement on Advance Notice of Military Exercises, signed after Exercise Brasstacks (1986-87). Its Article 10 keeps warships three nautical miles apart in international waters. Pakistan says the collision happened in its EEZ; the Exclusive Economic Zone under UNCLOS gives resource rights, not a right to exclude foreign ships.
Numbers and dates to remember
- 6 April 1991: agreement on advance notice of military exercises signed.
- Article 10: minimum three nautical miles (about 5.56 km) between naval ships and submarines.
- Six or more destroyer or frigate-sized ships: threshold for a major naval exercise under the agreement.
- June 2011: PNS Babur and INS Godavari incident.
- PNS Hunain: pennant F-273, commissioned 26 July 2024, built by Damen in Romania.
- EEZ: up to 200 nautical miles; territorial sea: up to 12 nautical miles.
Where to go next
- 1991 India-Pakistan Agreement on Advance Notice of Military Exercises: the rule India says was broken.
- Exclusive Economic Zone under UNCLOS: what Pakistan's EEZ claim does and does not mean.
- India-Pakistan confidence-building measures: the wider family of risk-reduction pacts.
- Exercise Brasstacks (1986-87): the crisis that produced the 1991 agreement.
Go deeper: are old CBMs enough for crowded seas?
The case that the 1991 agreement still works. It gave India a precise, agreed standard to cite. Without it, a protest would rest only on general seamanship rules. The agreement has survived wars, terror attacks and long breaks in dialogue, which shows that both sides value predictability even when relations are poor. The India-Pakistan confidence-building measures as a whole have lasted because they are narrow and technical.
The case that it is out of date. The agreement was drafted with land exercises in mind, after Exercise Brasstacks (1986-87). Critics say that at sea it offers little beyond a distance rule. The 2026 collision was handled through diplomatic protests, with each side summoning the other's Chargé d'affaires.
The legal argument. Pakistan's claim that the collision took place in its EEZ is a claim about resources and jurisdiction, not about sovereignty. The Exclusive Economic Zone under UNCLOS preserves freedom of navigation for other states. Article 10 of the 1991 India-Pakistan Agreement on Advance Notice of Military Exercises applies in international waters, so the two readings of the location lead to different arguments about which rules apply.
Options discussed by analysts. A dedicated incidents-at-sea agreement, similar to arrangements that other rival navies have used, could add communication procedures, signals and a regular review meeting. Critics reply that no new text will help unless both navies follow the rules they already have.
1991 India-Pakistan Agreement on Advance Notice of Military Exercises
The rule India says Pakistan broke.
In one line: A 1991 bilateral agreement that requires India and Pakistan to give advance notice of major military exercises and keeps their warships three nautical miles apart in international waters.
What it contains
The Agreement between India and Pakistan on Advance Notice on Military Exercises, Manoeuvres and Troop Movements was signed on 6 April 1991. Its purpose is to prevent crises caused by misinterpreting military intentions. Each side must notify the other of major exercises and troop movements near the border. For navies, a major exercise is identified by a threshold of six or more destroyer or frigate-sized ships.
Article 10
Article 10 says naval ships and submarines of the two countries must keep a minimum distance of three nautical miles, about 5.56 km, from each other in international waters. India cited this article after the PNS Hunain collision in September 2026.
Where to go next
Exclusive Economic Zone under UNCLOS
Why an EEZ claim does not close the sea to other navies.
In one line: The Exclusive Economic Zone is a belt of sea up to 200 nautical miles from a country's coast in which that country has rights over resources, while other states keep freedom of navigation.
The zones of the sea
The UN Convention on the Law of the Sea (UNCLOS) measures maritime zones from the coastal baseline. The territorial sea extends up to 12 nautical miles and is under the coastal state's sovereignty. Beyond it, the EEZ extends up to 200 nautical miles. In the EEZ the coastal state has sovereign rights for exploring and using resources such as fish, oil and gas, but it does not have full sovereignty.
Why it is in the news
Pakistan says the collision with an Indian warship took place in its EEZ. India says it happened in international waters. Because foreign ships may navigate in an EEZ, the dispute turns on which safety rules applied, not on whether the Indian ship could be there.
Where to go next
India-Pakistan confidence-building measures
The family of pacts that manage India-Pakistan military risk.
In one line: Confidence-building measures are practical arrangements that make India and Pakistan's military behaviour more predictable, without settling their political disputes.
The main measures
- 1988: agreement not to attack each other's nuclear installations.
- 6 April 1991: agreement on advance notice of military exercises, manoeuvres and troop movements.
- 6 April 1991: agreement on preventing airspace violations.
These measures are narrow and technical. They survive even when talks on bigger issues stop.
Why they matter now
The September 2026 collision shows both their value and their limits. India had a clear rule to cite, but the dispute was handled only through diplomatic protests. Earlier, in June 2011, PNS Babur and INS Godavari were involved in a similar incident.
Where to go next
Exercise Brasstacks (1986-87)
The crisis that pushed both sides to sign the 1991 agreement.
In one line: Brasstacks was a large Indian military exercise near the Pakistan border in 1986-87 that Pakistan read as a possible prelude to war, creating one of the tensest episodes in their relations.
What happened
Brasstacks was an Indian Army exercise held close to the border with Pakistan. Pakistan viewed its size and location with alarm and moved its own forces, and the two sides came close to a crisis. The episode showed how an exercise meant as a test of readiness can be misread as preparation for attack.
Why it matters
The lesson of Brasstacks was that each side needed to know in advance what the other's forces were doing. This led to the 1991 agreement on advance notice of military exercises, whose Article 10 India invoked after the September 2026 collision at sea.
Where to go next
Take the 17 September 2026 quiz: 30 Prelims-style questions with answers