Twenty percent of the global oil supply flows through the Strait of Hormuz, a narrow stretch of water that separates Persian Gulf countries like Iran, Iraq and Kuwait from the rest of the world. From May 15 to June 15, more than 1,000 tanker ships traveled the strait. Many were destined for places as far away as China and South Korea. The gulf region has been rocked by instability in recent months, threatening the flow of oil through the strait. Six tankers have been attacked since May amid escalating tensions between Iran and the United States.
After the Trump administration pulled out of the Iran nuclear deal last year, the United States began to tighten its sanctions on the country. The measures, although not adopted by all nations, allow the United States to punish companies and countries that engage in trade with Iran. Some countries were initially granted waivers under the sanctions, but many have stopped buying oil from Iran to avoid the risk of being punished by the United States. As a result, Irans exports have plummeted.