S. 271(1)(c) Penalty-Concealment –No penalty can be imposed where (i) income is added or disallowance is made on estimate basis, (ii) books of account cannot be produced for reasons beyond control, (iii) disallowance is made as per retrospective insertion of S. 37(1) Explanation & (iv) allegation regarding concealment vs. furnishing inaccurate particulars is vague & uncertain. [ S.37(1) ]