Best judgment assessment: requirement of notice and opportunity to be heard before AO determines taxpayer's liability under reformed assessment framework.
Clause 271 creates a mechanism for best judgment assessment where the AO may assess income or loss when an assessee defaults on filing returns or complying with statutory notices; the AO must consider all relevant materials, issue a show cause notice affording an opportunity of being heard (subject to an exception where an earlier notice suffices), and determine the sum payable based on his best judgment, with certain interpretative ambiguities left for administrative or judicial clarification.