US tightens the noose on Iran’s oil routes as Chabahar waivers expire—India weighs its next move

On April 25, 2026, the US Navy destroyer USS Rafael Peralta intercepted the Iranian tanker M/T HERBY in the Indian Ocean, citing its role in a blockade of Iranian ports. The tanker was reportedly returning to Iran from Indonesia after delivering two million barrels of oil. The action underscores a tightening of maritime interdiction pressure at the same time that US sanctions carve-outs tied to regional infrastructure are approaching their end date. Separately, reporting indicates that a US sanctions waiver on Iran’s Chabahar port is set to end on April 26, 2026, potentially putting a 23-year connectivity effort at risk. Strategically, the cluster links two pressure points: direct enforcement against Iranian oil flows and the conditionality of sanctions relief for connectivity projects. The US appears to be using both naval interdiction and time-bound waivers to constrain Iran’s ability to monetize exports and to limit the strategic value of ports like Chabahar. For Iran, the immediate loss of predictable waiver coverage would raise the cost of sustaining trade and logistics relationships, while for the US it offers leverage without requiring a broader diplomatic package. India, meanwhile, is considering options on its stake in Chabahar—ranging from temporarily divesting—suggesting it is balancing commercial exposure, sanctions compliance risk, and regional connectivity goals. Market and economic implications cut across oil, shipping, and regional trade finance. The interception of a tanker carrying two million barrels highlights near-term risk premia for Iranian-linked crude movements and can translate into higher freight and insurance costs for vessels operating in the Indian Ocean corridor. In parallel, the end of the Chabahar waiver threatens to disrupt trade routes that support broader regional commerce, potentially affecting demand expectations for logistics services and port-adjacent supply chains. For Venezuela, separate coverage notes that easing US sanctions has enabled liquidity injection and a partial revival of oil activity, but institutional and political uncertainty remains a constraint—an environment that can influence global supply expectations and the relative attractiveness of sanctioned versus re-opened barrels. What to watch next is the operational and legal sequence around April 26, 2026, and whether enforcement escalates beyond interdictions into broader restrictions on maritime access. Key indicators include additional US naval actions in the Indian Ocean, changes in tanker routing behavior for Iranian-linked vessels, and any formal guidance on Chabahar compliance after the waiver expiry. For India, trigger points include whether it executes a temporary divestment, seeks a renewed waiver, or restructures its exposure to reduce sanctions risk. In the near term, market participants should monitor shipping insurance pricing, port throughput signals at Chabahar, and any follow-on announcements that clarify whether the connectivity project will be paused, renegotiated, or effectively wound down.

Geopolitical Implications

• 01

  US enforcement and waiver deadlines are tightening Iran’s economic options.

• 02

  Chabahar’s disruption would weaken a strategic connectivity corridor for regional trade.

• 03

  India’s stake review signals sanctions compliance reshaping South Asia infrastructure decisions.

• 04

  Maritime pressure increases the risk of miscalculation in the Indian Ocean.

Key Signals

• —More US interdictions involving Iranian-linked tankers.
• —Official US guidance on what remains permitted at Chabahar after April 26.
• —India’s decision on divestment or restructuring of its Chabahar stake.
• —Insurance and routing changes for Iranian crude movements.