A. Regulations Not Retroactive: The regulations prescribed by this Chapter shall not be construed to require the removal, lowering or other changes or alteration of any structure or tree not conforming to the regulations as of the effective date hereof or otherwise interfere with the continuance of any nonconforming use. Nothing herein contained shall require change in the construction, alteration or intended use of any structure, the construction or alteration of which was begun prior to the effective date hereof, and is diligently prosecuted.
B. Marking And Lighting: Notwithstanding the preceding provision of this Section, the owner of any nonconforming structure or tree is hereby required to permit the installation, operation and maintenance thereon of such markers and lights as shall be deemed necessary by the City to indicate to the airport hazards. Such markers and lights shall be installed, operated and maintained at the expense of the City. (Ord. 475, 1974)