What Happened
- Indian-flagged crude tankers, including VLCCs Sanmar Herald and Jag Arnav, were intercepted and fired upon by Islamic Revolutionary Guard Corps (IRGC) gunboats while attempting to transit the Strait of Hormuz
- Iran sent mixed signals — briefly indicating the strait was open, then firing on vessels attempting passage — causing Indian and Greek crude tankers to turn back
- The incidents occurred amid a broader US naval blockade of Iranian ports and an ongoing ceasefire from the 2026 US-Israel-Iran war that had begun on 8 April
- Ship tracking data showed at least one Indian tanker (Desh Garima) successfully crossed the strait while multiple others were forced to reverse course
- India's Ministry of External Affairs (MEA) summoned Iranian Ambassador Dr. Mohammad Fathali to lodge a formal diplomatic protest
Static Topic Bridges
Strait of Hormuz — Geography and Strategic Significance
The Strait of Hormuz is a narrow waterway connecting the Persian Gulf to the Gulf of Oman and the Arabian Sea. It is the world's single most important oil transit chokepoint, with no viable alternative sea route for Gulf oil exporters. The strait is bordered by Iran to the north and the UAE and Oman to the south.
- Width: approximately 55–95 km; the navigable shipping lanes are each about 3.2 km wide, separated by a buffer zone
- Approximately 20 million barrels per day of crude oil and petroleum products transited the strait in 2025 — roughly 25% of all global seaborne oil trade
- About 20% of the world's LNG also passes through the strait
- ~84% of crude flows through Hormuz head to Asian markets; China, India, Japan, and South Korea collectively receive approximately 69% of all Hormuz crude flows
- Over 60% of India's crude oil imports originate from Gulf countries, making Hormuz critical to India's energy security
Connection to this news: Any closure or disruption of the Strait of Hormuz directly threatens India's energy supply chain. India imports nearly 87% of its crude oil, and a significant portion transits Hormuz, making the IRGC's interdiction of Indian-flagged vessels both an energy security and diplomatic crisis for India.
IRGC (Islamic Revolutionary Guard Corps) — Role and Naval Mandate
The IRGC, also known as Sepah or Pasdaran, is a branch of the Iranian Armed Forces constitutionally mandated to protect the Islamic Republic's ideological integrity — distinct from the regular Iranian Army (Artesh), which handles conventional defence. The IRGC Navy (IRGCN) operates in the Persian Gulf and Strait of Hormuz using asymmetric warfare doctrines: fast-attack craft, naval mines, and swarm tactics rather than traditional naval engagements.
- Established after the 1979 Islamic Revolution; reports directly to Iran's Supreme Leader
- Designated as a Foreign Terrorist Organization (FTO) by the US in April 2019 — the first time a state actor's military branch received this designation
- The IRGCN functions as Iran's de facto coast guard in the Persian Gulf and strait approaches
- Doctrine: asymmetric or "guerrilla navy" tactics — prioritises harassment, interdiction, and mine warfare over fleet engagement
Connection to this news: The IRGCN's firing on Indian commercial vessels represents a use of its asymmetric naval doctrine to enforce Iran's claimed Hormuz closure — even against neutral third-country ships not party to the US-Iran conflict.
UNCLOS and Right of Transit Passage Through International Straits
Under the United Nations Convention on the Law of the Sea (UNCLOS, 1982), all vessels — including warships and commercial ships — have the right of "transit passage" through straits used for international navigation (Part III, Articles 37–44). This right cannot be suspended by the coastal state during peacetime.
- Transit passage (UNCLOS Part III, Articles 34–45) applies to straits overlapping territorial waters where there is no alternative high-seas route
- Strait of Hormuz qualifies as such a strait: it connects the Persian Gulf to the high seas
- Under transit passage, ships must proceed continuously and expeditiously; coastal states may regulate safety, pollution, and fishing but cannot suspend transit
- India has ratified UNCLOS (1995); Iran has also ratified UNCLOS but has historically disputed its application in the Persian Gulf
- Distinct from "innocent passage" (territorial sea, Part II, Section 3): transit passage allows submarines to travel submerged and warships do not require prior notification
Connection to this news: India's protest to Iran's envoy invokes international maritime law — specifically the right of transit passage — as the legal basis for demanding resumption of unimpeded navigation for its commercial vessels.
Key Facts & Data
- Indian tankers targeted: Sanmar Herald (VLCC carrying ~2 million barrels of Iraqi crude), Jag Arnav
- Successful Hormuz transit: Desh Garima (appeared to cross on April 18)
- Iran's Ambassador to India: Dr. Mohammad Fathali (summoned by MEA, April 18, 2026)
- Global oil through Hormuz: ~20 million barrels/day; ~25% of seaborne global oil trade
- India's crude import dependence: ~87% imported; Gulf countries supply ~60% of imports
- India's Hormuz-dependent crude: approximately 50% of India's crude imports pass through the strait
- UNCLOS: adopted 1982, entered into force 1994; 168 parties
- India ratified UNCLOS: 1995