West Texas Intermediate futures for February delivery plunged to $29.75 (-2.11%), while Brent crude dropped to $28.05 (-3.08%) amid concerns that the global supply glut could worsen once Iran boosts exports. On Sunday the UN confirmed that Tehran fulfilled its obligations under a landmark deal to curb its nuclear programme. Iranian deputy oil minister said his country was ready to increase its crude oil exports by 500,000 barrels per day. Many analysts expect prices to remain under pressure.

U.S. crude oil inventories are ample and China's slowing economy is unable to absorb additional supplies.