Global oil price started the week on a slight fall due to global oversupply and slowing economic growth.
On Monday, the oil price opened at $40.90 and slowly retreated to as low as $40.87, according to official data.
Prices were at $40.90 at 8:34 GMT+2, representing a decline of 1.55 percent compared to Friday levels.
On Friday, oil hit $42 per barrel mark on the expectation of OPEC, non-OPEC producers' oil freeze agreement scheduled for April 17.
The highest level of the day was $42.45 on Friday, official data shows.
Meanwhile, U.S. WTI also observed a fall to $38.80 at 08:34 GMT+2, declining by 2.14 percent since Friday.