Section 170(1)(iii) in The Bihar Government Estates (Khas-Mahal) Manual, 1953
(iii)that should the property or any part of it be resumed by Government for a public purpose the compensation payable therefor shall not exceed the amount (if any) paid to Government for the grant plus the cost or the present value, whichever is less, of the buildings or other structures erected with the previous sanction of Government or other competent authority; and