Chennai, May 25: PMK founder Dr S Ramadoss today said Congress should have honoured the agreement reached with the DMK on the allocation of portfolios in the Manmohan Singh government at the Centre. He told reporters at Meenambakkam airport on arrival from New Delhi that it was a "mistake" on the part of the Congress on going back on its commitment. "I hope that the mistake will be rectified soon and the DMK ministers assume office at the Centre," he said. Bureau Report