Penalty for not filing return

If you provide good reason penalty nil or penalty will be rs.1.00 lac

As per Section 271F of the Income tax Act, 1961 

if a assessee fails to file his ITR on or before end of relevent AY, the AO may impose a penalty of Rs. 5000/-.

e.g. Mr. X filed his ITR on 31.12.2011 (due date - 30.9.2011) for AY 2011-12. Whether he is liable to pay any penalty??

Ans:- No, Mr. X have filed his ITR on or before end of relevant AY i.e. 31.03.2012. He is not liable for penalty u/s 271F.

Also, as per section 273B, the penalty can be waived if sufficient cause for the delay has been furnished to AO.