(3) In fixing the fair rent of a residential building the Controller may allow, if the basic rent: i) in the case of a building in existence before the Ist January, 1939 (a) does not exceed Rs.25 per mensem an increase not exceeding 81 xab per cent on basic rent; (b) exceed Rs.25 per mensem, an increase but does not exceed RS.50 per mensem, an increase not exceeding 12 1/2 per cent on such basic rent; (c) exceeds RS.50 per mensem an increase not exceeding 25 per cent on such basic rent; 111 (ii) in the case of building, constructed on or after the Ist January, 1939 (a) does not exceed Rs.25 per mensem, an increase not exceeding 25 per cent on such basic rent; (b) exceeds Rs.25 but does not exceed Rs.50 per mensem, an increase not exceeding 37 1/2 per cent on such basic rent; (c) exceed Rs.50 per mensem, an increase not exceeding 50 per cent on such basic rent; (4) in fixing the fair rent of a scheduled building the controller may allow, if the basic rent (i) in the case of a building in existence before the Ist January, 1939 (ii) does not exceed Rs.25 per mensem, an increase not exceeding 13 1/2 per cent on such basic rent; (b) exceeds Rs.25 but does not exceed Rs.50 per mensem, an increase not exceeding 17 xab per cent on such basic rent; (c) exceed Rs.50 per mensem, an increase not exceeding 303 percent on such basic rent; (ii) in the case of a building constructing on or after the Ist January, 1939 (a) does not exceed Rs.25 per mensem an increase not exceeding 30 percent on such basic rent; (b) exceeds Rs.25 but does not exceed Rs.50 per mensem, an increase not exceeding 42 xab per cent on such basic rent; (c)exceeds Rs.50 per mensem, an increase not exceeding 55 per cent on such basic rent; 112 (5) In fixing fair rent of a non residential building or rented land the controller may allow, if the basic rent, (i) in the case of building in existence before the Ist January, 1939 or in the case of rented land; (a) does not exceed Rs.50 per mensem, an increase not exceeding 371/2 per cent on such basic rent; (b) exceeds Rs.50 per mensem, an increase not exceeding SO per cent on such basic rent; (ii) in case of building constructed after the Ist January 1939: (a) does not exceed Rs.50 per mensem, an increase not exceeding 50 per cent on such basic rent; (b) exceeds Rs. 50 per mensem, an increase not exceeding 100 per cent on such basic rent; (6) Nothing in this section shall be deemed to entitle the Controller to fix the rent of a building or rented land at an amount less than the rent payable for such building or rented land under a subsisting lease entered into before the first day of the January 1939.