Since early March a previously obscure waterway between Iran and Oman that very few people could name has become the subject of daily reporting around the world after Iran closed it as a response to the attack on Iran by the United States and Israel. The Strait of Hormuz, which remains closed to most ships, is now known around the world as the transit point for 20 percent of the world's oil and high percentages of key materials including fertilizers such as ammonia (23 percent), urea (34 percent) and phosphate (20 percent), helium (30 percent), and sulfur (24 percent), all of which are derived from or are co-products of oil or natural gas except phosphate.
On the other side of the Arabian peninsula, a long-festering conflict between Ansar Allah (which controls part of Yemen) and Saudi Arabia has escalated. Not surprisingly, Ansar Allah, also known as the Houthis, have resorted to a tactic used previously in the conflict. They have closed the Bab el-Mandeb Strait near their the territory to Saudi vessels.
The strait connects Red Sea shippers with ocean-going routes to Asia. This includes ships coming through the Suez Canal on the northern end of the Red Sea. The Houthis say that commercial shippers not serving Saudi Arabia may continue using the strait, but many have chosen to avoid it as the Houthis attack Saudi ships. In practice this means primarily a prohibition on Saudi oil tankers which carry Saudi Arabia's main export. For now, the Saudi ships are taking a trip around Africa to reach Asia despite the added costs. But the Houthis have shown they can hit Saudi ports on the Red Sea and could escalate to shut down even this traffic.