Section 66(1)(b) in The Gujarat Municipalities Act, 1963
(b)every contract for the execution of any work for the supply of any materials or goods which will involve an expenditure exceeding one thousand rupees, shall be in writing and shall be sealed with the common seal of the municipality and shall specify the work to be done or the materials or goods to be supplied, as the case may be, the price to be paid for such work, materials or goods and in the case of contract for work, the time or times within which the same or specified portions thereof shall be completed.