Rising tensions involving Iran have sharply reduced shipping activity through the Strait of Hormuz, one of the world’s most important energy routes. The narrow channel normally sees around 80 oil and gas tankers pass through each day, transporting roughly a fifth of global oil supplies along with large volumes of natural gas.

Recent shipping data, however, shows that only a handful of vessels have attempted the crossing, with just two tankers passing through one day and only one the following day. Many ships are now holding position on either side of the strait as companies and crews weigh the risks of entering the area. Although the passage has not been formally shut down, analysts say the situation amounts to a practical standstill, with traffic largely halted due to security concerns...