Section 79(1)(iv) in The Gujarat Town Planning and Urban Development Act, 1976
(iv)the contribution levied on a plot used, allotted or reserved for a public purpose or for the purpose of the appropriate authority which is beneficial partly to the owners of land or residents within the area of the scheme and partly to the general public shall be calculated in proportion to the benefit estimated to accrue to the general public from such use, allotment or reservation.