It shall be unlawful for the occupant of any lot or lots or the owner of any vacant lot or lots within the corporate limits to allow snow, sleet, mud, ice, or other substance to accumulate on the sidewalks or to permit any snow, sleet, ice, mud, or other substance to remain upon said sidewalk. All sidewalks within the business district shall be cleaned within five (5) hours after the cessation of a storm, unless the storm or fall of snow shall have taken place during the night, in which case the sidewalk shall be cleaned before eight-thirty (8:30) o'clock A.M. the following day; provided, sidewalks within the residential areas of the Municipality shall be cleaned within twenty-four (24) hours after the cessation of the storm. (Ref. 17-557 RS Neb.)