Which war is having the biggest impact on diesel prices – Iran or Ukraine?

As well as being a major exporter of crude oil, the Middle East is also a significant global hub for the production of diesel.

In 2025 the Gulf states – Saudi Arabia, UAE, Kuwait, Bahrain and Oman – were exporting around 1.4 million barrels of diesel per day.

In September 2026 that had fallen to around 670,000 barrels per day.

This sharp decline has been driven by the impact of the US-Iran war on the flow of exports of refined diesel from the Gulf states through the Strait of Hormuz.

Traffic flows in the waterway have been badly disrupted by Iranian strikes on tankers and the US blockade of Iran’s ports.

While estimates from ship-tracking firms suggest the flow of crude oil through the waterway returned close to pre-war levels last month – due, in part, to the US navy helping to protect shipping – the flow of refined diesel from the Middle East has remained far below pre-war levels.