What is the India-Pakistan conflict at sea about? | Explained
On the evening of September 15, an Indian Navy warship and a Pakistan Navy vessel collided in the North Arabian Sea, in what both sides describe as international waters.
India's account: an Indian Navy ship on a routine surveillance mission was approached at high speed by a Pakistani naval vessel, leading to the collision; New Delhi called the Pakistani unit's conduct "unacceptable and unprofessional."
Pakistan's account: the incident occurred while its navy was conducting a biennial exercise, and it accused an Indian naval vessel of aggressive manoeuvres near a Pakistani ship operating close to what it described as its Exclusive Economic Zone (EEZ).
Both countries summoned each other's senior diplomats in their respective capitals to lodge formal protests.
India stated that the Pakistani vessel's conduct violated Article 10 of the 1991 Agreement on Advance Notice on Military Exercises, Manoeuvres and Troop Movements, a bilateral confidence-building measure (CBM).
The 1991 Agreement on Advance Notice on Military Exercises, Manoeuvres and Troop Movements
This is one of the oldest India-Pakistan confidence-building measures (CBMs), signed in New Delhi on 6 April 1991, years before the 1999 Lahore Declaration and the 2003 ceasefire agreement. Its objective is to reduce the risk of misunderstanding, accidental escalation, or military incidents by requiring each side to give the other advance notice of major military activity near the international border/Line of Control and in adjoining waters. It sits alongside other India-Pakistan CBMs such as the 1988 Agreement on the Prohibition of Attack against Nuclear Installations and Facilities and the 1991 Agreement on Prevention of Air Space Violations.
Key Details
- Signed: 6 April 1991, a bilateral, non-treaty CBM (not a UN-registered treaty).
- Advance notice periods specified: 15 days for designated air and naval exercises, 60 days for corps-level exercises, and 90 days for army-level exercises.
- "Major naval manoeuvres" under the pact are defined as operations involving six or more combat vessels of frigate/destroyer size or above operating in formation, or vessels entering the other country's EEZ.
- Article 10 specifically requires naval ships and submarines of the two countries to maintain a minimum separation of three nautical miles from each other while operating in international waters, precisely to avoid accidental collisions of the kind alleged on September 15.
India's diplomatic protest rests explicitly on Article 10's three-nautical-mile separation rule, framing the collision not just as an accident but as a CBM violation — a distinction Indian statements have used to place responsibility on Pakistan without political attribution.
India-Pakistan Confidence-Building Measures (CBM) Architecture
CBMs are non-treaty, procedural arrangements between adversarial states designed to reduce the chance that routine military activity is misread as hostile intent, thereby lowering the risk of unintended escalation between two nuclear-armed neighbours. India and Pakistan have built a layered CBM architecture since the late 1980s covering nuclear installations, airspace, prior notification of exercises, and a Director-General of Military Operations (DGMO) hotline.
Key Details
- 1988: Agreement on the Prohibition of Attack against Nuclear Installations and Facilities (in force since 1991; both sides annually exchange lists of nuclear facilities on 1 January).
- 1991: Agreement on Advance Notice on Military Exercises, Manoeuvres and Troop Movements (the pact at issue here).
- 1991: Agreement on Prevention of Air Space Violations and for Permitting Over-Flights and Landings by Military Aircraft.
- Ceasefire understanding along the Line of Control (LoC), first agreed in 2003 and reaffirmed in 2021, is enforced through the weekly DGMO hotline.
The naval collision tests the durability of this CBM framework at sea, an domain with fewer established de-confliction mechanisms than the land border/LoC, and is a reminder that CBMs depend on good-faith compliance rather than any enforcement mechanism.
Exclusive Economic Zone (EEZ) under UNCLOS
An Exclusive Economic Zone is a maritime zone extending up to 200 nautical miles from a coastal state's baseline, within which that state has sovereign rights over exploration and exploitation of natural resources, but where other states retain freedom of navigation and overflight, unlike in territorial waters (12 nautical miles). The concept is codified in the UN Convention on the Law of the Sea (UNCLOS), 1982, to which both India and Pakistan are parties.
Key Details
- Territorial waters: up to 12 nautical miles from the baseline, where the coastal state has full sovereignty.
- Contiguous zone: up to 24 nautical miles, for customs/immigration/sanitary enforcement.
- EEZ: up to 200 nautical miles, resource rights only; foreign warships retain high-seas freedoms of navigation.
- Under the 1991 CBM, a naval vessel entering the other country's EEZ during an exercise itself triggers the "major manoeuvre" notification requirement.
Pakistan's claim that the incident occurred near its EEZ during an exercise, versus India's claim of international waters, is central to the dispute over which country's forces initiated the close approach and which provision of the 1991 Agreement was breached.
- The 1991 Agreement on Advance Notice on Military Exercises, Manoeuvres and Troop Movements was signed on 6 April 1991 as a bilateral India-Pakistan CBM.
- Article 10 of the Agreement mandates a minimum 3-nautical-mile separation between the two navies' ships and submarines operating in international waters.
- UNCLOS defines EEZ as extending up to 200 nautical miles from a state's baseline, distinct from the 12-nautical-mile territorial sea.
- The collision occurred on the evening of 15 September 2026 in the North Arabian Sea, prompting formal diplomatic protests from both New Delhi and Islamabad.