Analysis of seizure of the Iran-Linked Tankers by India – Indian Blog of International Law

Kshitij Saruparia and Apeksha Kachhawaha

On 5 February 2026, the Indian Coast Guard intercepted three tankers, the Stellar Ruby, the Asphalt Star and a vessel then sailing as the Al Jafzia, roughly one hundred nautical miles west of Mumbai. All three tankers had been sanctioned by the United States Treasury in 2025 for moving Iranian oil. India’s Ministry of Defence’s press release described it as an operation against a syndicate using mid-sea transfers to move cheap oil to motor tankers, “thereby evading substantial duties owed to coastal states, including India.” The words are precise enough to sound legal and vague enough to avoid saying which law they invoke.

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The point of interception – one hundred nautical miles from the Indian coastline – is within India’s two-hundred-nautical-mile exclusive economic zone (EEZ) but outside the twelve-nautical-mile territorial sea where India’s exercises maritime sovereignty. The point of interception is significant because the United Nations Convention on the Law of the Sea (UNCLOS) provides a graded sovereignty across different zones of sea. Such Zones, relevant for this piece, include the Territorial Sea, Contiguous Zone, EEZ and High Seas. In this post we analyse India’s actions as per the relevant international law. In the next post, we discuss the curious absence of international law arguments in the domestic proceedings that have followed the interception.

Relevant UNCLOS framework

Under the UNLCOS, the Territorial Sea extends up to 12 nautical miles from the coastal State’s baseline, within which the State exercises sovereignty subject to the right of innocent passage for foreign vessels (Arts. 2–3). A baseline is the line along the coast, normally the low-water line, from which the breadth of the Territorial Sea, Contiguous Zone, EEZ, and Continental Shelf is measured (Arts. 5–7, UNCLOS). Beyond the Territorial Sea lies the Contiguous Zone, extending up to 24 nautical miles from the baseline, where the coastal State may exercise control necessary to prevent or punish infringements of its customs, fiscal, immigration, or sanitary laws (Art. 33). The EEZ extends up to 200 nautical miles from the baseline, within which the coastal State enjoys sovereign rights for the exploration, exploitation, conservation, and management of natural resources, together with certain jurisdictional powers (Arts. 55–57). Beyond the EEZ are the High Seas, comprising all parts of the sea not included within the EEZ, Territorial Sea, Internal Waters, or Archipelagic Waters of any State, where all States enjoy the freedoms of navigation, overflight, fishing, scientific research, and other internationally lawful uses of the sea (Arts. 86–87).

Article 33 of the UNCLOS, explains the limits of a contiguous zone and the kind of jurisdiction a state can exercise in it. This Zone ‘may not extend beyond 24 nautical miles from the baselines from which the breadth of the territorial sea is measured’. Within this Zone, a coastal state may may exercise the control necessary to prevent and punish ‘infringement of its customs, fiscal, immigration or sanitary laws and regulations within its territory or territorial sea’. The tankers in question were boarded more than four times that distance out, on the Coast Guard’s own account of where the interception happened. India’s action, therefore, was beyond the limits of jurisdiction prescribed by the Article 33, but it falls within the territorial limit of its EEZ. The question then is, whether India’s actions were permitted under the relevant UNCLOS clause on the EEZ.

Article 56 gives the coastal state sovereign rights to explore and exploit living and non-living resources, and jurisdiction over artificial islands, marine research and environmental protection. A ship-to-ship transfer of crude oil between vessels in transit seems not be covered by this article though. Article 56(1)(c) adds a broad clause covering “other rights and duties provided for in this Convention,” but such a clause only picks up rights the Convention creates elsewhere. It does not create one on its own, and no other provision gives India a jurisdiction over cargo moving through its EEZ.

The one place UNCLOS does give a coastal state customs jurisdiction inside the EEZ is Article 60, and it is narrower than it sounds. Article 60(1) covers artificial islands, installations and structures the coastal state itself has built. Article 60(2) then gives it customs, fiscal, health, safety and immigration jurisdiction over those structures specifically. A tanker under way is not a structure India constructed, and nothing in the Convention’s use of the term anywhere else treats a passing vessel as one.

Comparative Analysis 1: Saiga

In M/V Saiga (No. 2), the International Tribunal for the Law of the Sea (ITLOS) decided this question and reached the same conclusion on facts close enough to test it for the purposes of this piece. The case concerned a dispute between Saint Vincent and the Grenadines and Guinea over Guinea’s arrest and detention of the M/V Saiga outside its territorial sea for alleged customs violations arising from offshore refuelling, raising questions about the exercise of coastal State enforcement jurisdiction under UNCLOS. The Tribunal held that Guinea had no right to apply its customs laws to a tanker bunkering fishing vessels inside Guinea’s EEZ. The Tribunal was explicit about where coastal state customs power in the EEZ begins and ends. As it explained, such jurisdiction exists in the territorial sea, in the contiguous zone for the purposes Article 33 lists, and in respect of installations under Article 60(2). Guinea’s own domestic courts had convicted the Saiga’s master of smuggling and confiscated the ship. ITLOS found that that conviction rested on a customs law and that Guinea had no authority to extend into its EEZ.

The judges were not unanimous, however, on how much weight the drafting history deserved. Judge Nelson (at pages 6 to 7 of his separate opinion) warned against reading too much into decades-old rejection of a wider EEZ customs proposal by eighteen African states, since a proposal which states declined to adopt does not by itself prove they meant to forbid it. Even though that caution is important, this piece does not lean on the drafting history to look beyond the provisions of the UNCLOS.

What makes Saiga worth reading past the headline holding is what Guinea actually argued, because Guinea tried almost every route India’s press release gestures toward and abandoned each one under its own scrutiny. Guinea’s argument and interpretation of the UNCLOS was analysed in the Separate Opinion of Judge Vukas. He shows that Guinea explicitly declined to find the claim on Article 56’s resource rights, conceding that bunkering fishing vessels is a commercial activity rather than an exploitation of the zone’s resources. Guinea then argued a broader “public interest” in protecting its fiscal revenue, then a doctrine of necessity borrowed from general international law, and only last, in Judge Vukas’s words, “with some reluctance,” a fallback under Article 59. Guinea’s own Rejoinder provides the most useful sentence in the whole record – Article 59, it said, “applies only when there is a lacuna in the law which is not present here.” Guinea, while trying to find a customs power in its EEZ, told the tribunal that the residual-rights provision did not fit a customs claim.

The necessity argument fared no better. Guinea invoked the doctrine of state necessity that the International Court of Justice had set out shortly before in the Gabčíkovo-Nagymaros case. There, the ICJ had held that an act is excused only if it is the sole means of protecting an essential interest against grave and imminent peril, and does not seriously harm another state’s interest in the process. ITLOS applied that test and found Guinea had shown neither element. Losing tax revenue from unlicensed bunkering, however real, is not a peril grave and imminent enough to justify extending a customs law two hundred kilometres past where it was meant to stop.

Article 59 deserves more than the passing mention Guinea gave it, because it is the one provision built for exactly this kind of gap. It provides that where the UNCLOS does not attribute a right or jurisdiction to either the coastal state or other states in the EEZ, a conflict between them is resolved ‘on the basis of equity and in the light of all the relevant circumstances, taking into account the respective importance of the interests involved to the parties as well as to the international community as a whole’. Writing on the EEZ regime, Robert Beckman and Tara Davenport describe activities the Convention leaves unassigned as the precise gap Article 59 exists to close. Several states, including Germany, the Netherlands and Sweden, have formally linked the provision to security interests in their own UNCLOS declarations. India could have also linked justified its actions under this article as an equitable balancing act between India’s interest in policing sanctions-evading transfers and the flag states’ interest in freedom of navigation.

Comparative Analysis 2: Arctic Sunrise Arbitration

A more recent arbitration shows what it looks like when the Permanent Court of Arbitration (PCA) actually works through every plausible jurisdictional basis a coastal state can reach for. It is the Arctic Sunrise arbitration case where Russia had boarded and detained a Dutch-flagged Greenpeace vessel in its own EEZ after activists tried to climb the Prirazlomnaya oil platform, an actual installation within Article 60’s terms. Russia charged the crew with piracy, then hooliganism, then terrorism, then tried to justify the boarding as protection of its resource rights and marine environment. The PCA rejected each of these claims, mostly because the facts did not support the label Russia had reached for. It also rejected procedural condition like the continuity hot pursuit demands. More relevantly, the case included questions of security interests – something which India’s press release gestures towards. The PCA considered whether Russia could act on a reasonable suspicion that the vessel threatened the platform and found no reasonable basis for that suspicion on the facts. In the light of this decision, it seems even more difficult to justify India’s actions since the Cargo it detained never touched Indian shores or transferred between vessels with no fixed installation in sight.

Conclusion

Justification for India’s actions does not depends on what actually happened between the three tankers before the Coast Guard boarded them. It depends only on what UNCLOS permits a coastal state to do about it from within its own EEZ, and the answer, on the government’s own account of where the boarding took place, is narrower than the press release assumed. Guinea ran through every version of this argument at ITLOS and lost on all of them, conceding along the way that the one provision built for genuine gaps did not cover its case. India has not yet had to make that argument anywhere, because nothing since February has forced it to do so. The Ministry of Defence’s statement has not been challenged in an international court and moreover, as this analysis shows, it will be difficult to justify India’s actions asper that statement.

(This is a Guest-Post by Kshitij Saruparia and Apeksha Kachhawaha. Apeksha is an incoming Associate at ASV Legal LLP. She graduated from Maharashtra National Law University, Nagpur in 2026. Kshitij is an Advocate practicing at Rajasthan High Court. He graduated from NALSAR University of Law, Hyderabad in 2026.)