Saudi Arabia reported to OPEC that its crude oil production plunged again last month, hitting the lowest since 1990 as renewed hostilities between the US and Iran squeezed the kingdom’s export routes. Riyadh notified OPEC’s secretariat that its output tumbled by 1.9 million barrels a day to 6.238 million a day, according to a monthly report from the organization obtained by Bloomberg. That’s an even lower level than the previous wartime nadir reached in April, which was the lowest figure reported by the kingdom since the beginning of the Gulf War.