Section 18(2) in The Gujarat Slum Areas (Improvement, Clearance and Redevelopment) Act, 1973
(2)On receipt of such declaration, the prescribed 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, furnished, if any, and having such enquiry 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).
