World oil price continues to fall . It has fallen below $28 a barrel (equivalent of 159 liters)amid fears the lifting of Western sanctions on Iran could worsen the existing over supply problem .
The lifting of the Iran sanctions mean half a million barrels more oil per day could be produced , say analysts .
The decision to lift the sanctions against Iran came on Sunday after the International nuclear watchdog, the IAEA, said Iran complied with a deal designed to prevent it developing nuclear weapons .