Time limit for assessments after search or requisition clarified, with procedural exclusions and extension mechanisms affecting limitation periods. The substituted provision prescribes that assessments or reassessments under section 153A must be completed within twenty-one months from the end of the financial year in which the last authorisation for search under section 132 or requisition under section 132A was executed, with special rules for 'other persons' under section 153C allowing nine months from handover of seized or requisitioned materials if later; extensions to thirty-three months apply where a section 92CA(1) reference is made, and specified periods (e.g., stays, audit directions, valuation references, and certain proceedings) are excluded in computing limitation, subject to minimum sixty-day safeguards.