If, after any such public hearing, the Council finds that the public necessity, health, safety or welfare requires such removal and such underground installation within a designated area, and/or if the Council, in said finding, finds one or more of the reasons required under and by virtue of Section A (1)(a) of Rule No. 20 of the Commission, the Council shall, by resolution, declare such designated area an Underground Utility District and order such removal and underground installation. Such resolution shall include a description of the area comprising such district and shall fix the time within which such removal and underground installation shall be accomplished and within which affected property owners must be ready to receive underground service. A reasonable time shall be allowed for such removal and underground installation, having due regard for the availability of labor, materials and equipment necessary for such removal and for the installation of such underground facilities as may be occasioned thereby.