Oil fell below $118 a barrel on Monday, pressured by concern over the euro zone debt crisis, although supply worries due to tightening Western sanctions on Iran checked the slide. The outlook for Europe's economy worsened in April, raising the likelihood that oil consumption will slow. Fresh data for Germany, France and the euro zone showed a much faster rate of economic contraction than had been expected. The wobbly financial state of some big euro zone economies has unsettled markets, despite signs at the start of the year that Europe's long-running debt crisis was easing.