Where, by reason of topographical conditions, district border line situations, immediately adjoining existing developments, or because of other unusual circumstances, the strict application of any provision of this chapter would result in exceptional practical difficulty or undue hardship upon the owner of any specific property, the Commission in passing upon applications shall have the power to vary or modify strict adherence to this chapter, or to interpret the meaning of this chapter so as to relieve such difficulty or hardship, provided that such variance, modification or interpretation shall remain in harmony with the general purpose and intent of this chapter so that the general character of the district shall be conserved and substantial justice done. In granting variations, the Commission may impose such reasonable and additional stipulations and conditions as will, in its judgment, better fulfill the purpose of this chapter.