Section 20A(2) in The Slum Areas (Improvement And Clearance) Act, 1956
(2)On receipt of such declaration, the competent authority shall by order require the owner of the building to furnish to it, within such time as may be prescribed, the plans of the work of improvement or re-erection of the building and estimates of the cost thereof and such other particulars as may be necessary and shall, on the basis of such plans and estimates and particulars, if any, furnish and having regard to the provisions of sub-section (3) of section 20B and after holding such inquiry as it may think fit, provisionally determine the rent that would be payable by the tenant if he were to be replaced in occupation of the building in pursuance of the declaration made by him under sub-section (1).