Introduction

The Strait of Hormuz is a strait with three major bordering states- Iran in the North, and Oman and the United Arab Emirates (UAE) in the South. It connects the Gulf of Oman with the Persian Gulf and the Arabian Sea. It has high economic importance because about 30% of the world’s liquefied gas and 25% of oil pass through the strait.

In India, the world’s second-largest importer of LPG, 62-65 per cent of the supply comes from the Gulf countries, including Saudi Arabia, Qatar and the UAE.[1] For crude oil requirement, India depends on 80 per cent imports, which come from these countries. The Strait of Hormuz provides passage for such imports to India from these countries.

In the context of other Asian countries too, the strait holds great economic relevance, and therefore, its closure by Iran as a consequence of armed conflict with the US and Israel has led to a global energy crisis.

Background

On 28 February 2026, the US and Israel launched a joint attack on Iran under the operation Epic Fury, thus killing the supreme leader of Iran, Ayatollah Ali Khamenei. Consequently, Iran closed the Strait of Hormuz for the US, Israel, Europe and their Western allies. However, it did not clearly state whether India or other states can pass through it.

This closure raised a very important question of international law: whether Iran can close the strait unilaterally? In the previous article we have already discussed in detail the rights of bordering and other states in the strait.

Can Iran close the Strait of Hormuz during wartime?

The legality of the action of Iran under international law can be understood by analysing the following points:

Iran is not a party to UNCLOS: Iransigned UNCLOS in 1982 but has not ratified it. Therefore, it does not consider itself bound by it. Consequently, it can close the Strait of Hormuz, thus denying the right to transit passage to other States.

Another factor to consider is whether the ‘right to transit passage’ is a rule of customary international law. This point is still debatable. While the right to innocent passage has been recognised as a customary international law, the status of the ‘right of transit passage’ is still unclear.

Many times, it has been argued by the US that the ‘right to transit passage’ is also a customary international law. However, the ICJ has not yet provided any ruling on this point. If this right has attained the status of customary international law, then Iran can not suspend this right for any state, even in wartime.

Application of UNCLOS during armed conflict: The treaties related to the subject matters provided in annexure of the Draft articles on the effects of armed conflicts on treaties 2011 continue to operate during wartime. It includes ‘treaties establishing or modifying land and maritime boundaries. It means UNCLOS continue to apply even during wartime.

Exercise of sovereign rights: CanIran justify its closure of the Strait of Hormuz as exercising sovereign rights in parts of its territorial sea? This justification is not right in the sense of international law because UNCLOS creates a balance between exercise of sovereign rights by the states in strait and the rights of foreign states of transit passage.

Adverse impact of global trade: Further, closing the Strait of Hormuz as a retaliatory measure against an attack by Israel and the USA is also problematic because such a closure is adversely affecting global energy trade. The closure has hindered free trade across countries.

Therefore, the action of Iran is not at all proportional to the actions of Israel and the US because its retaliatory measures are affecting other nations too and are leading to escalation of the conflict, which is not consistent with international law.

Conclusion

It can be concluded that even if Iran is not a party to UNCLOS, it cannot arbitrarily deny the transit passage to other States. Even if the customary law status of ‘right of transit passage’ is not clear, it can be inferred that, as this right originates from the freedom of navigation, which itself is a customary international law, right to transit passage also forms the part of customary international law, thus binding on Iran irrespective of its ratification of UNCLOS.

Further, although Iran is not a WTO member and therefore not bound by its agreements, it cannot, in the name of security, impede other states’ free trade rights. This is against basic principles of trade law. In such a case, Iran must establish how the US and Israel might pose a threat to Iran through the Strait of Hormuz.

Therefore, closing the Strait of Hormuz, which is vital to global energy trade, is a violation of international law. Iran should have taken measures proportional to the actions of Israel and the USA in order to stop the violation of international law by these two states. However, Iran itself got involved in the escalation of the situation by harming other States which are unconnected to the actual conflict. Therefore, Iran must be stopped from violating customary international law and stop the excessive action of closing the Strait of Hormuz.

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This article is authored by Astha Priya.

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[1] LPG Imports India: How gas is sourced, supplied and distributed nationwide