77. (1) When by the making of any improvement, development or re-housing scheme, any land in the area comprised in the scheme which is not required for the execution thereof will, in the opinion of the Authority, be increased in value, the Authority, in framing the scheme, may, in lieu of providing for the acquisition of land, declare that a betterment fee shall be payable by the owner of the land or any person having an interest therein in respect of the increase in value of the land resulting from the execution of the scheme. (2) Such betterment fee shall be an amount equal to one-half of the increase in value of the land resulting from the execution of the scheme, and shall be calculated upon the amount by which the value of the land on the completion of the execution of the scheme estimated as if the land were clear of buildings exceeds the value of the land prior to the execution of the scheme estimated in like manner.