The World Bank signaled the possibility of a "more pronounced slowdown" in China, the world's second largest economy after the United States. It also cut its growth forecast for Asia. Red-hot growth in emerging markets like China and India helped boost oil consumption coming out of the global recession.
U.S. benchmark crude fell 55 cents to close at $89.33 per barrel in New York. The contract hasn't closed lower since Aug. 2.
In London, Brent crude, which is used to price international varieties of oil, fell 20 cents to $111.82 a barrel.
At the pump, U.S. gas prices remain stubbornly high. The national average for gasoline rose 3 cents over the weekend to $3.818 a gallon ($1 per liter). But Californians are now paying an average of $4.668 a gallon ($1.23 a liter), the highest price in the U.S., after a jump of 50 cents a gallon in the past week. Some motorists there are paying over $5.
In response, California Gov. Jerry Brown has ordered state smog regulators to allow cheaper winter-blend gas to be sold three weeks early. And Sen. Dianne Feinstein has called for a federal investigation because she doesn't think the higher prices are related to supply and demand.
In other energy futures trading in New York:
• Natural gas gained less than a penny to reach $3.40 per 1,000 cubic feet.
• Heating oil lost a penny to close at $3.14 per gallon.
• Wholesale gasoline fell 6 cents to finish at $2.89 per gallon.