“This notification shall come into force with effect from the 1st day of April 2024 and shall, accordingly, apply in relation to the assessment year 2024-25 and subsequent assessment years” According to the Central Board of Direct Taxes (CBDT) notification. Cost Inflation index is used for calculating long-term capital gains arising from sale of immovable property, securities and jewellery after adjusting inflation when they file income tax returns (ITR) next year.