(1)Where the Secretary considers that-(a)any building or portion thereof is, by reason of its having no plinth, or having a plinth of insufficient height, or by reason of the want of proper drainage or ventilation or by reason of impracticability of cleansing, attended with danger of disease to the occupiers thereof or to the inhabitants of the neighbourhood, or is, for any reason, likely to endanger the public health or safety; or(b)a block or group of buildings is, for any of the said reasons, or by reason of the manner in which the buildings are crowded together, attended with such risk as aforesaid,he may, by notice, require the owners or occupiers of such buildings or portions thereof or, at his option, the owners of the land occupied by such buildings or portions thereof to execute such work or to take such measures as he may deem necessary for the prevention of such danger.