Block assessment confined to search material, not post-search investigation, so the addition could not be sustained.

Block assessment under Chapter XIV-B is confined to undisclosed income found as a result of search or requisition, and cannot be expanded to include income detected later through independent investigation, survey, or post-search material unless it is traceable to evidence unearthed during the search. Sections 158BC and 158BB create a special and limited procedure that is not a substitute for regular assessment. On that basis, an addition founded only on material discovered after the search was impermissible, and the Tribunal's deletion of the block assessment addition was affirmed against the Revenue.

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Issues: Whether block assessment under Chapter XIV-B could include income detected only through post-search investigation and not from materials found during the search.

Analysis: The scope of block assessment is confined to undisclosed income found as a result of search or requisition. Income discovered later through investigation, survey, or other post-search material cannot be treated as the basis for addition in block assessment unless it is traceable to evidence unearthed during the search. The statutory scheme under sections 158BC and 158BB is a special and limited procedure and is not a substitute for regular assessment.

Conclusion: The addition based on material found only after the search was not permissible in block assessment, and the answer was against the Revenue.

Final Conclusion: The departmental challenge to the deletion of the block assessment addition failed, and the decision of the Tribunal on the core question was affirmed.

Ratio Decidendi: Block assessment under Chapter XIV-B can be founded only on evidence or material found as a result of search or requisition, and cannot be expanded to cover income discovered later through independent investigation.

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