S. 251 : Appeal-Commissioner (Appeals)-Powers-Setting aside of matter back to the AO-Failure to file return-Best judgement assessment-No power to set aside the matter w.e.f 1st June 2001-the matter is restored back to the CIT(A) with a direction to call for a remand report from the AO and then adjudicate the matter. [S. 139, 142(1), 144]