I was told some time ago that the reason diesel was priced so highly in the UAE and Oman was because unscrupulous dealers were filling their tankers with subsidised diesel (before the price was artificially raised) and taking it over the border to Yemen and selling it at much higher prices. Now that the governments here are realising that subsidisation is unsustainable, and they start to subject all the fuel types to market forces, voila, the price of diesel should come down from and petrol should go up. That's the theory.