The oil campaign over Romania and against the synthetic oil plants in the Ruhr—in which most oilfields had been destroyed, captured or damaged by 1945—triggered a critical fuel shortage from the autumn of 1944 onwards which denied the "Luftwaffe" the resources to capitalise on its numerical strength. Paradoxically, production was able to replace the relatively small losses and operational serviceability reached an all-time high since ground crews had more opportunity to work on machines. The "Luftwaffe" was still capable of taking a toll on Bomber Command on occasion, but unless more powerful radars and communications could be introduced in time it was doubtful British air superiority at night could be challenged. The impotence of the night fighter force "as an organisation" was demonstrated during the attack on Dresden when the second wave of Allied bombers was hardly opposed. Operation Clarion, launched later that month, was not adequately opposed either.