Reference year update: section 55 revises the base year for cost indexation affecting capital gains computation. The Finance Act, 2017 substitutes the earlier base-year reference with a later base-year reference in the cost indexation provisions of section 55, replacing that reference in the specified clause of sub-section (1) and in the corresponding clause of sub-section (2), effective from the relevant assessment year commencement, thereby altering the base year applied for computing indexed cost of acquisition for capital gains purposes.