The decision is a serious negative for the oil market, given that oil demand is rising too slowly to sop up all of the extra supply.

Oil prices fell on Monday afternoon to their lowest level of the year after the OPEC oil cartel and its allies affirmed plans to gradually increase crude production beginning in April.

Oil producers group Opec's decision to restore supply next month will add to an oil market glut expected this year, resulting in a decline in prices, experts say. On Monday, the alliance of producers said it would proceed with a "gradual and flexible" unwinding of voluntary production cuts of 2.