Notice to remove nuisance

70. The Corporation, if satisfied of the existence of a nuisance, shall serve a notice on the author of the nuisance or if he cannot be found, then on the owner occupier of the building or premises on which the nuisance arises or continues, requiring him to remove it within the time specified in the notice and to execute such works and do such things as may be necessary for that purpose and if the Corporation thinks it desirable (but not otherwise) specifying any works to be executed to prevent a reccurence of the said nuisance; Provided that— (a) Where the nuisance arises from any want or defect of a structural character, or where the building or premises are unoccupied, the notice shall be served on the owner; (b) Where the author of the nuisance cannot be found and it is clear that the nuisance does not arise or continue by the act or default or sufferance of the owner or occupier of the building or premises, the Corporation may remove the same and may do what is necessary to prevent the recurrence thereof.