(1) If it appears to the Head of the Physical Planning and Development Division that the amenity of any area is seriously injured by reason of the ruinous, unsafe or dilapidated condition of any building, or by the condition of any garden, vacant site or other open land, or the deposit of refuse, spoil or derelict vehicles, or the occupation of land or a public road for any unauthorised purpose, including the repair of vehicles, the Head of the Physical Planning and Development Division may serve on the owner or occupier of the land, or the person responsible for the injury, a notice requiring such steps to be taken for abating the injury as may be specified therein.