Capital Gain Assessable value

Head income tax
Descripttion cost of acquisition on compulsory acquisition
Dear all,
One of my clients land compulsorily acquired by govt in 1979. After going for appeal in various courts the amount received in 2022.
In this case since the transfer happened in 1979 and settlement in 2022, assessee offering for tax ib fy 22-23.
What would be the cost of acquisition since the acquisition happened in 1979 itself. Can we take fmv on 2001? From where we can get this value as on 2001?