Documents relating to the assessee were found during a search conducted on another person. Although the Assessing Officer recorded satisfaction that proceedings were required to be initiated under section 153C, he completed the assessment under section 143(3) without issuing notice under section 153C or obtaining approval under section 153D. Information obtained under the Right to Information Act confirmed these lapses. The Tribunal held that failure to invoke the mandatory provisions of section 153C constituted a fundamental jurisdictional defect rendering the assessment unsustainable. (AY. 2021-22).