¹[3A. (1) No owner or occupier of a building shall, without obtaining previous permission from the Authorised Officer or the Committee, as the case may be, use the building for the purpose other than that mentioned in the sanction. (2) When the ²[Authorised Officer] is satisfied that the existing use of any land or building does not conform the scheme of land utilisation indicated in the Master Plan, the ³[Authorised Officer] may, by an order in writing, direct the owner, occupier or the person in charge of the land or building to discontinue such use and, in the case of a building also to remove or dismantle such building: Provided, however, that the owner, occupier or the person in charge of the land or building shall be given six months' time before effect is given to the order of discontinuance of such use and twelve months' time before effect is given to the order of removal or dismantlement of the building: Provided further that no existing or further use of any land or building for combined residential and commercial purpose shall be discontinued or prohibited unless, in any particular case, such use militates against the dominant character of the scheme of land utilisation as indicated in the Master Plan and constitutes a nuisance generally to the zone and particularly to the neighbourhood in which the land or building is situated. ⁴[* * *]