It is hereby declared by the Council that the regulations contained herein are necessary in order to prevent and to lessen congestion in the streets and highways; to secure safety from fire, flood, panic and other dangers; to protect the public health and general welfare; to provide adequate light and air; to prevent the overcrowding of land; to avoid undue concentration of population; to facilitate the adequate provision of transportation, water, sewage, schools, parks, and other public requirements; to conserve the value of buildings and encourage the most appropriate use of land throughout the City, all in accordance with a Comprehensive Plan.