Oil prices fell to their lowest level in 20 months on Tuesday, despite efforts by the OPEC cartel to stem the slide, as weak economic growth continued to reduce consumption around the world.

Lower energy prices are providing some welcome relief for struggling consumers, but a 59 percent decline in oil prices since their summer peak also shows how radically the prospects of the global economy have darkened in recent months.

At an emergency meeting last month, members of the Organization of the Petroleum Exporting Countries agreed to reduce their output, as of Nov. 1, to slow the price slide.

While there is no official tally of OPEC production, several members  including Algeria, Qatar, the United Arab Emirates and Kuwait  have signaled in recent days that they had begun paring their production.