When the tract proposed to be subdivided is of such unusual size or shape or is surrounded by such development of unusual conditions that the strict application of the requirements contained in these regulations would result in substantial hardships or injustice, the Council upon recommendation of the Planning and Zoning Commission may vary or modify such requirements so that the developer is allowed to develop the property in a reasonable manner, but, at the same time, the public welfare and interests of the City and surrounding area are protected and the general intent and spirit of these regulations are preserved.