Interviews | Security | South Asia

Geospatial Intelligence Expert Y. Nithiyanandam on Why the Hormuz Strait is No Longer a Neutral Global Common

“Access now depends on where you stand with Tehran, whether you are willing to comply with its rerouting demands, and whether you have quietly negotiated your place in the new order.”

Topography (elevation above land surface) & bathymetry (depth below water surface) around the Strait of Hormuz.

Soon after the United States and Israel launched air and missile strikes on Iran on February 28, Iran hit back by not only targeting Israel and U.S. allies in the Gulf with missiles and drones but also by blockading the Strait of Hormuz through unconventional means. In recent weeks, the U.S. has blocked ships from entering or leaving Iranian ports through a conventional blockade. As a result, the center of gravity of Gulf War 3.0 appears to have shifted from Iran to the Strait of Hormuz.

The Hormuz crisis has hit Asian economies the hardest. While some tankers have been hit as they attempted to cross the strategic waterway, others have managed to pass through without incident. Hundreds of ships are said to be sitting idle in nearby ports.

Geospatial Intelligence (GEOINT) expert Professor Y Nithiyanandam, who heads the Geospatial Research Program at the Takshashila Institution in Bengaluru, has been using AIS-based observation, satellite imagery, and other open-source tools to monitor developments in the Strait of Hormuz and its impact on India. In an interview with The Diplomat’s South Asia editor Sudha Ramachandran, Nithiyanandam said that the important question thrown up by the 2026 Hormuz crisis is not whether this vital waterway is open or closed but “who controls the terms on which it remains open.” A state does not have to shut down the entire strait to flex its muscles. All it needs to do is “to make those few critical lanes uncertain enough to undermine commercial confidence, insurance coverage, and scheduling reliability.”

In the past, people viewed the Strait of Hormuz as a waterway through which oil and gas passed, one that gave Iran, the country that controls it, a binary option — to keep the strait open or shut. You wrote that the 2026 Hormuz crisis has changed our understanding of the strait. How?

For decades, the Strait of Hormuz was viewed through a very binary lens: either it stayed open to global shipping, or Iran tried to close it through conventional military escalation. That mindset grew out of the Tanker War era (1984-1988), when both Iran and Iraq targeted commercial shipping in the Gulf and Western planners concluded that while Iran could disrupt traffic, it could not hold the strait against superior U.S. naval power over time.

The 2026 crisis upended that assumption. What Iran has shown is that it does not have to physically shut the strait or defeat the U.S. Navy to exercise meaningful control over Hormuz; it only has to make passage sufficiently uncertain. That is the core conceptual shift.

Rather than mounting a classic blockade, Iran leaned on geography and a toolkit of selective disruption: sea mines, drones, Automatic Identification Systems (AIS) suppression, Global Navigation Satellite System (GNSS) spoofing, and calibrated incidents that steadily eroded confidence in the safety of transit. The waterway remained technically open, but operationally degraded. Within weeks, maritime traffic collapsed by almost 95 percent – not because of sustained naval confrontation in the strait, but because shipowners, insurers, and seafarers no longer saw Hormuz as certainly navigable.

This produced the largest disruption to oil flows through a single chokepoint in modern history, and the shock was felt most sharply in Asia. Before the crisis, roughly 20 million barrels of oil and petroleum products transited Hormuz each day, along with over 112 billion cubic meters of LNG annually, much of it bound for China, India, Japan, and South Korea. India alone relied on the strait for around 45–50 percent of its crude imports and about 52 percent of its LNG. So, the crisis revealed something broader: the critical vulnerability is no longer primarily about Western naval access to the Gulf; it is about the fragility at the heart of Asian energy supply chains.

What 2026 made clear is that chokepoint control has outgrown the binary model entirely. Physical obstruction and digital interference now operate alongside something harder to counter — the deliberate management of uncertainty. The question is no longer whether Hormuz is open or closed. It is who controls the terms on which it remains open.

You have argued that “Iran did not try to ‘close’ the Strait of Hormuz in the traditional sense. It tried to change how the strait works.” Could you explain?

Iran’s approach in 2026 was more subtle. Rather than stopping every vessel, Tehran set out to redesign the operating logic of the strait. Passage became conditional, uncertain, and selective.

At one stage, ships were increasingly routed through a narrow corridor in Iranian‑controlled waters between Larak and Qeshm Islands, where authorities began demanding transit clearances and, for some categories of traffic, charging newly introduced tolls. These tolls were later formalized in Iranian domestic law, giving the regime a legal‑administrative framework for what began as a de facto “toll‑gate” system. Some vessels moved through under tacit understandings; others delayed their voyages, switched off tracking systems, rerouted, or avoided the corridor altogether.

During the ceasefire announcement around the 40th day of the war, Iran initially tried to present this new transit system as a joint Iran–Oman arrangement, with reports of roughly a $2 million charge per vessel to give it a veneer of regional consent and legality. Oman publicly pushed back, citing its obligations under international maritime law and distancing itself from the scheme. Within weeks, by about the 53rd day of the war, the language of co‑management had faded, but Iranian control remained in practice: ships relying on the Omani side of the traffic lanes also began to encounter pressure and risk. AIS‑based ship-tracking showed that the supposedly neutral bypass lane was no longer neutral at all, but a space where vessels were exposed if they tried to avoid Iranian‑managed routes.

The shallow Iranian shelf is well‑suited to mine‑laying and asymmetric interdiction, while the deeper Omani corridor is effectively the only viable route for Very Large Crude Carrier (VLCC)‑class tankers. That allows large commercial shipping to be compressed into predictable channels without a formal blockade.

Iran was not trying to close the Strait of Hormuz. It was trying to own the conditions under which it stayed open.

What are the insights you have drawn from satellite imagery/AIS data on the strategy adopted by ships from India, China, Japan, and South Korea to deal with the uncertainty in the Strait of Hormuz?

The AIS and other remotely sensed data revealed something striking very early in the crisis: the maritime system effectively split into two realities, “the visible sea” and “the actual sea.”

At one point, satellite‑based Synthetic Aperture Radar (SAR)........

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