Two tankers moved through the Strait of Hormuz on August 24, representing the fewest commodity vessels to move through the waterway in a single day since early May.

According to Reuters, the two crossings -- by one very large gas carrier and one very large crude carrier -- fell far short of the 10-day average of 14 daily commodity vessels tracked by freight intelligence service Kpler. However, Kpler cautioned that its count could change, given that some ships have been traveling through the strait with their tracking systems switched off. Separately, cargo tracking service Vortexa estimates that overall oil flows through the strait totaled roughly 5 million barrels on August 24, down from the seven-day average of 6-7 million barrels.

Even at that seven-day average, oil flows through Hormuz remain well below the more than 20 million barrels per day that moved through the strait before the conflict. Iran has further tightened the squeeze in recent weeks, after blacklisting 45 tankers for violating its passage rules, and warning other vessels against conducting ship-to-ship transfers.

Ships on Iran's list could be detained, fined, or have their cargo confiscated. It's unclear what the vessels did to violate Iran's rules for transiting the strait, although Tehran has previously said ship owners should obtain clearance before crossing through an approved route through the strait.