If a person wants to bring an action under Law of Torts for the tort of public nuisance, he must prove…

Public nuisance is primarily a crime, and a private person can sue in tort for it only if he proves special damage, that is, an injury particular to him that is direct and substantial and beyond what the public generally suffers; this is what "the injury was direct and substantial only to him" expresses. Showing that the public at large was affected, or that the act is a crime, is not enough for an individual action; a suit for the public as a whole lies instead under section 91 of the Code of Civil Procedure.