text: A bus company's efforts to cut global warming emissions have led to services being disrupted by cold weather. First Eastern Counties Buses, which runs services in Norfolk, Suffolk and Cambridgeshire, said bio-diesel had turned waxy in sub-zero temperatures. The thicker consistency of the diesel meant fuel lines became blocked. The company said it had suspended use of the bio-diesel, and was refuelling buses with ultra low-sulphur diesel which is not temperature sensitive.