The 1991 Agreement Between India and Pakistan is a bilateral military confidence building measure signed in New Delhi on April 6, 1991, that established rules covering major military exercises, manoeuvres and troop movements by the two countries. Its purpose was to reduce the possibility that military activity by one side would be misread as preparation for an attack. The agreement remains relevant because it also contains specific provisions governing encounters between Indian and Pakistani naval vessels and military aircraft.
The agreement has returned to the spotlight in September 2026 following a collision involving a Pakistani naval vessel and an Indian Navy warship in the North Arabian Sea. India cited Article 10 of the 1991 agreement, which requires naval ships and submarines of the two countries to remain at least three nautical miles apart while operating in international waters. Pakistan has disputed India’s characterization of the incident and has presented its own account of the encounter.
Takeaways
The 1991 agreement remains an important India Pakistan military confidence building measure, combining advance notification procedures with specific rules for naval and air operations.
What Is the 1991 Agreement Between India and Pakistan?
The formal title of the principal agreement is the Agreement Between India and Pakistan on Advance Notice on Military Exercises, Manoeuvres and Troop Movements. It was signed by the two governments in New Delhi on April 6, 1991. The agreement was designed to create a government-level mechanism for advance notification and to reduce the risk that military activity would be interpreted as preparation for a broader conflict.
This is important in the India Pakistan context because both countries maintain large conventional military forces and have historically operated close to one another on land, in the air and at sea.
The agreement therefore functions as a confidence building measure, rather than a conventional arms control treaty. It does not prohibit India or Pakistan from maintaining military forces or conducting exercises. Instead, it establishes restrictions and notification procedures intended to make military activity more predictable.
Two Different India Pakistan Agreements Were Signed in 1991
A common source of confusion is that India and Pakistan signed two separate military agreements on April 6, 1991.
The first is the agreement concerning:
- Advance notice of military exercises
- Manoeuvres
- Troop movements
- Naval operations
- Military aircraft separation
The second is the Agreement on Prevention of Air Space Violations and for Permitting Over Flights and Landings by Military Aircraft. That separate agreement specifically addresses airspace violations and military aircraft operating near the two countries’ airspace. The United Nations Treaty Collection records the airspace agreement separately from the advance-notice agreement.
For the September 2026 naval collision, the agreement receiving attention is the advance-notice and military manoeuvres agreement, particularly its Article 10 naval separation provision.
Why the 1991 Agreement Was Created
The central problem addressed by the agreement was miscalculation.
Large military exercises can create ambiguity during periods of political tension. The movement of armored formations, artillery, aircraft or naval units can appear similar to preparations for an actual operation.
The agreement therefore establishes rules intended to distinguish exercises and routine military activity from preparations for offensive operations.
The agreement states that the land, naval and air forces of India and Pakistan should avoid major military manoeuvres close to one another. Where exercises fall within the areas covered by the agreement, the strategic direction of the main force should not be toward the other side and logistics should not be built up close to it.
This makes the agreement a risk reduction mechanism rather than a restriction on overall military capability.
What Does the Agreement Say About Naval Forces?
One of its most significant provisions is the definition of a major naval exercise.
The agreement identifies a major naval exercise as one involving six or more ships of destroyer or frigate size and above, operating together and crossing into the other country’s Exclusive Economic Zone.
The agreement also contains a separate operational safety provision.
The Three Nautical Mile Rule
Article 10 states that naval ships and submarines belonging to the two countries are not to close to less than three nautical miles from one another while operating in international waters.
Three nautical miles is approximately 5.56 kilometers.
The stated purpose is to reduce the possibility of accidents between Indian and Pakistani naval platforms.
This provision is particularly significant because naval forces routinely operate in environments where ships may monitor, shadow or observe one another.
A separation requirement provides an additional bilateral safety mechanism beyond ordinary navigation and maritime safety procedures.
2026 India Pakistan Naval Collision
The relevance of Article 10 increased sharply after a September 15, 2026 collision between an Indian Navy warship and Pakistan Navy vessel PNS Hunain in the North Arabian Sea.
Indian officials said the incident occurred in international waters and accused the Pakistani vessel of approaching at high speed and manoeuvring unsafely. India subsequently summoned Pakistan’s Charge d’Affaires and lodged a formal diplomatic protest.
India specifically cited Article 10 of the 1991 agreement, arguing that the conduct violated the bilateral requirement concerning separation between naval ships.
Pakistan has provided a different account of the incident. The Associated Press reported that Pakistan characterized the Indian vessel’s actions as provocative and dangerous and said the collision occurred during a Pakistani naval exercise.
The competing accounts are important because the 1991 agreement does not itself determine responsibility for a collision. Establishing responsibility requires examination of the actual movements, navigational circumstances, communications, location and other available evidence.
Military Aircraft Rules Under the Agreement
The 1991 agreement also contains detailed provisions concerning military aircraft.
Combat aircraft, including:
- Fighters
- Bombers
- Reconnaissance aircraft
- Jet military trainers
- Armed helicopters
are generally required to remain at least 10 kilometers from the other country’s airspace, including its Air Defence Identification Zone.
There are specific provisions for aircraft operating from designated air bases.
On the Indian side, these include:
- Jammu
- Pathankot
- Amritsar
- Suratgarh
On the Pakistani side, the agreement identifies:
- Pasrur
- Lahore
- Vehari
- Rahim Yar Khan
For combat aircraft operating from these bases, the agreement specifies a 5-kilometer separation from the other country’s airspace.
The agreement also permits certain unarmed transport, logistics and observation aircraft to operate closer to the other country’s airspace under specified conditions.
Advance Notification of Military Exercises
The notification provisions are designed to provide the other side with enough information to distinguish an exercise from a potentially hostile military deployment.
The agreement permits the other country to request clarification concerning:
- The assembly of military formations
- The geographical extent of an exercise
- Its direction
- Its duration
For immediate troop movements, information can be passed through established military communication channels, including the hotline arrangements specified by the agreement.
This communication architecture is significant because strategic warning time can be more important than the size of the force involved during periods of heightened tension.
Comparison and Data Summary
| Element | 1991 Agreement Provision |
|---|---|
| Formal focus | Advance notice of military exercises, manoeuvres and troop movements |
| Signing date | April 6, 1991 |
| Signing location | New Delhi |
| Parties | India and Pakistan |
| Military domains | Land, naval and air forces |
| Major naval exercise | Six or more destroyer/frigate-size ships operating in company and crossing the other country’s EEZ |
| Naval separation | At least 3 nautical miles in international waters |
| Combat aircraft separation | Generally 10 km from the other country’s airspace and ADIZ |
| Designated air bases | 5 km aircraft separation provision |
| Unarmed aircraft | Specific closer-operation provisions |
| Main objective | Reduce miscalculation and accidental escalation |
| Legal character | Bilateral military confidence building measure |
| Current relevance | Naval safety, military notification and crisis management |
Source: Agreement text and supporting treaty documentation.
How the Agreement Fits Into Modern Military Operations
The strategic environment of 1991 was very different from the one facing India and Pakistan today.
Both countries now operate more capable:
- Multirole fighter aircraft
- Long-range surveillance systems
- Maritime patrol aircraft
- Unmanned aerial systems
- Guided weapons
- Networked command systems
- Modern surface combatants
- Submarines
- Electronic warfare systems
This technological growth increases the importance of predictable military behaviour.
A modern military platform can detect and track another platform from much greater distances than was possible decades ago. At the same time, sensors can generate uncertainty if commanders do not know whether an observed deployment represents training, surveillance, deterrence or preparations for combat.
For this reason, bilateral rules governing notification, distance, communication and military transparency can remain relevant even as military technology changes.
The Agreement Compared With the Separate Airspace Pact
| Issue | Advance Notice Agreement | Airspace Agreement |
|---|---|---|
| Date | April 6, 1991 | April 6, 1991 |
| Main purpose | Military exercises, manoeuvres and troop movements | Prevention of airspace violations |
| Naval provisions | Yes | No comparable central naval provision |
| Three nautical mile rule | Yes | No |
| Military aircraft separation | Yes | Yes |
| Airspace overflights | Limited provisions | Central focus |
| ADIZ provisions | Yes | Yes |
| Military confidence building | Yes | Yes |
The distinction matters when analyzing incidents. Not every Indian Pakistan military incident in the air is automatically governed by the same 1991 document.
The United Nations Treaty Collection separately identifies the two agreements.
Earlier Naval Incident Shows the Rule Is Not New
Article 10 has been relevant before.
In June 2011, Pakistan formally protested an incident involving PNS Babur and INS Godavari. Pakistan’s Foreign Ministry said the Indian ship had undertaken dangerous manoeuvres during operations involving the merchant vessel MV Suez and argued that the incident violated the 1991 agreement.
The 2011 incident demonstrates that Article 10 was not created specifically for the 2026 collision. The provision has existed as a bilateral naval safety measure since 1991.
Operational Limitations
The agreement provides a framework for managing military risk, but it cannot eliminate the possibility of incidents.
Several limitations remain.
1. Enforcement Depends on Political Will
The agreement establishes obligations and procedures, but its practical effectiveness depends heavily on whether both governments and military commands continue to follow them during periods of tension.
2. Attribution Can Be Difficult
Determining whether a particular movement violates an agreement can require detailed information about:
- Ship position
- Speed
- Course
- Maneuvering decisions
- Communications
- Exercise objectives
- Airspace boundaries
- EEZ boundaries
Public statements alone may not provide enough evidence to establish what occurred.
3. Modern Sensors Increase Interaction
Modern maritime surveillance and networked sensors make it easier for each military to detect the other’s platforms. That improves situational awareness but can also increase the number of close monitoring encounters.
4. The Agreement Does Not Cover Every Modern Threat
The 1991 framework predates today’s widespread use of military UAVs, cyber operations, autonomous systems and modern long-range precision weapons.
Those capabilities create new escalation-management challenges that were not central to the agreement when it was signed.
Why the 1991 Agreement Still Matters
The importance of the 1991 Agreement Between India and Pakistan is less about controlling the size of either country’s military and more about controlling the circumstances under which military forces interact.
The agreement creates several layers of risk reduction:
- Advance notification of major military activity
- Restrictions on major exercises near the other side
- Clarification mechanisms for military movements
- Naval separation requirements
- Military aircraft separation rules
- Communication procedures during emergencies
These mechanisms are particularly relevant between two nuclear-armed states with geographically close military forces.
The broader regional architecture also includes other bilateral confidence building measures. For example, India and Pakistan continue to exchange lists of nuclear installations under their separate 1988 agreement. India’s Ministry of External Affairs said the exchange on January 1, 2025 marked the 34th consecutive exchange of those lists.
Future Outlook
The September 2026 naval collision demonstrates why older military confidence building measures can retain operational relevance decades after their creation.
The underlying technology has changed considerably since 1991, but the core problem has not: military forces operating close to one another can create escalation risks when intentions are misunderstood or safety procedures are not followed.
Future India Pakistan risk reduction could therefore involve strengthening existing communication mechanisms and clarifying how older bilateral agreements apply to newer systems such as unmanned aircraft, advanced surveillance platforms and increasingly networked naval forces.
For naval operations specifically, the three nautical mile provision remains a clear and measurable safety rule. Its value depends on consistent adherence and effective communication between military commands.
Conclusion
The 1991 Agreement Between India and Pakistan remains one of the key bilateral military confidence building mechanisms governing interactions between the two countries.
Signed on April 6, 1991, it established procedures for advance notification of major military exercises, manoeuvres and troop movements while also setting specific rules for naval and air operations. Its Article 10 requires Indian and Pakistani naval ships and submarines to maintain a separation of at least three nautical miles when operating in international waters.
The September 2026 collision involving PNS Hunain and an Indian Navy warship has brought that provision back into focus. India has invoked Article 10, while Pakistan has disputed India’s account of the incident.
The episode highlights the continuing importance of military confidence building measures in South Asia. As India and Pakistan deploy increasingly capable aircraft, ships, submarines, unmanned systems and surveillance networks, mechanisms designed to prevent accidents and miscalculation remain an important part of crisis management.
