World oil prices fell below $50 a barrel Monday.
It is the first time the cost of crude oil for future delivery has been below that key level in New York trading since early October.
Analysts gave various reasons for the decline, including improved inventories of heating oil in the U.S. market.
World oil prices have surged about two-thirds since the start of this year, driven by strong demand at the same time a number of major oil exporting nations are having production problems.
Some information for this report provided by AFP and Reuters..