No custodian of a horse may permit its use or work on the public streets whenever:the real or effective temperature exceeds 92^° F. or falls below 20^° F., as announced by the local radio service; an official “snow emergency” is in effect; or because of adverse weather conditions, the Commissioner of Health or some other authorized official of the City issues a determination, by radio or other means, that it would be dangerous or unsuitable for a horse to be on the streets. If a horse is already in use when a condition described in subsection (a) of this section begins, the custodian must immediately return the horse, by the most direct route, to the stable from which it was obtained. City Code, 1976/83, art. 19, §32(h) Ord. 99-548 Ord. 11-573