(1) No habitable room shall have an area less than 9.50 sq. metres having a minimum width of 2.40 metres, where there is only one room. In case of more than one room, one of these rooms shall be not less than 9.50 sq. metres with a width of 2.40 metres at the minimum and the others shall not be less than 7.50 sq. metres in area with a minimum width of 2.10 metres.
(2) No habitable room shall have a height of less than 2.75 metres measured from the surface of the floor to the lowest point of the ceiling or the underside of any slab:
Provided that in the case of any centrally air-conditioned building, the height of any habitable room shall not be less than 2.4 metres measured from the surface of the floor to the underside of any slab or false ceiling, as the case may be:
Provided further that the height from the surface of the floor up to the beam shall not be less than 2.4 metres:
Provided also that in the case of any pitched roof, the average height shall not be less than 2.75 metres and the minimum height at eaves level shall be 2.1 metres.
(3) All rooms in any building irrespective 'of their use-group, utilized for human habitation, shall conform to subrules (1) and (2) of this rule.
(4) Any room to be used as retail shop shall have a minimum clear height of 2.3 metres measured from floor to bottom of the ceiling or beam, whichever is lower.