What Are The FSI Rules And Other Regulations For Construction in Mumbai?

Building Regulations in Mumbai | Building Bye-Laws in Mumbai

Please find below the various details related to FSI, TDR and other construction related terms applicable in Mumbai.

1. FSI allowed in Mumbai: varies with the location. For residential buildings is 1.33 from South Mumbai till Mahim in the West and Sion in the centre.  
    North of that it is 1.0.  This is called the base FSI. To this, one is allowed to add TDR or transferable developent rights (see below) to arrive at the total FSI. This works out to an additional FSI of 1. FSI is calculated using the Fungible FSI (see below) system, except in CRZ areas, where it follows the old system.
    For educational, healthcare and hospitality projects, FSI is 1.33 plus 300% extra, which is 1.33 x 4 = 5.32.

The following are not counted in FSI calculations:
• Basements
• Stilt Parking
• Staircases
• Lifts and lift lobby (lobby area to an extent equal to lift area, additional lobby areas are counted)
• Pump rooms, utility areas, security cabins
• Shafts
• Society Office upto 12 m2 if there are less than 20 apartments, and 20 m2 if more
• Gymnasium upto 2% of FSI area
• One Servants’ toilet per floor upto 2.2 m2 with access from lift lobby
• Refuge Areas and terraces
Normally, 15% of the plot must be reserved as a recreation area.  If the plot area is greater than 2,500m2, then this 15% is also subtracted from the total FSI of the plot. Note that this explanation pre-dates the concept of "Fungible FSI". See below for an explanation of fungible FSI.

What is FSI?
FSI or floor space index is the upper limit to the built space you may construct on a given plot. It is the ratio of allowed built-up area to the plot area.  For example, on a 10,000 ft2 plot which has an FSI of 2, you may construct a maximum of 20,000 ft2 of area, and no more. FSI can also be called FAR or floor area ratio. Certain types of spaces, such as basements, parking areas, and utility rooms, are exempt from FSI, which means that they do not need to be counted in the FSI calculations. As of 2015, this system is used to govern buildings in CRZ areas within Mumbai.

What is Fungible FSI?
The word fungible - from the latin root fungiblis - describes something that acts as a replacement for something else. The municipal corporation of Mumbai introduced this system to curb misuse of existing building regulations by developers. Developers would build space over and above the allowable FSI by the means of some grey areas in the building regulations. These grey areas centered around things that were free of FSI, or not counted in FSI calculations, such as flower beds, services shafts, and balconies. In the fungible FSI system, the allowable FSI on a plot is increased by 35%, with a maximum cap on the total construction area, with no exemptions. This serves to reduce 'overbuilding' on plots by developers. The fungible FSI seeks to act as a replacement for or a legalisation of the misuse of regulations, but with a clear mathematical limit that should not be exceeded. As of 2015, fungible FSI is applicable to all plots in Mumbai with the exception of those that fall under Coastal Regulation Zone (CRZ) limits. So if the base FSI on a plot is 1, and the TDR on the plot is also 1, then add 35% to each of them, making a total FSI of 2.7 for the plot. This is approximate, as there are some variations with respect to recreational grounds and other factors, which can reduce the total FSI available.

2. TDR: can be an additional 1 on FSI in normal areas, not in CRZ areas.  Areas given to road setbacks and recreational grounds (15% of the plot area) should be deducted from the TDR.  Therefore, if there are no setbacks, the TDR will be 0.85.

What is TDR?
Transferable Development Rights are a mechanism to reduce new construction in crowded areas and shift it to less dense parts of the city. In Mumbai, TDR was initiated to prevent new construction in south Mumbai and shift it northwards. It works as follows: say you own a 10,000 ft2 plot with an FSI of 1.3 in South Mumbai, on which you have an existing building with 8,000 ft2 of built-up area. To utilise your full FSI allowance, you would have to build 10,000 x 1.3 = 13,000 ft2 of space. This means you have 5,000 ft2 of extra capacity in your plot which you are not using. With TDR you can then sell this right to build 5,000 ft2 to someone north of you. You then cannot build more than the existing 8,000 ft2 on your plot.

3. Height of Building: depends on location and proximity to airport.  Height of a room should be less than 4.2m.

4. Setbacks / Open Spaces Required around building: Ht/3 for living spaces (bedrooms, living rooms) and Ht/5 for dead walls and toilets.  This can be overcome by paying a premium to the BMC. This is called open space deficiency. However the CFO will demand a clear 6mx6m for fire engine movement.

5. Min Size of Rooms: as follows:
 
                                       Min Area                Min Width
Habitable Rooms              9.5 m2                       2.4m
Toilets                              2.2 m2
Toilets (separate)             1.1 m2 (WC)            1.5 m2 (area of bath)
Kitchens (1 BHK Flats)      5.5 m2                       1.8m
Kitchens (2 BHK Flats)      7.5 m2                       2.1m

6. Balconies: in the fungible FSI system, the area of balconies is counted in FSI.

7. Refuge Areas: one every 24m in height, area not less than 4% of the occupied space existing till the next refuge area.

8. No. of staircases Required: two if the floor plate is more than 500m2 or the height more than 24m.  Each should be 1.5m wide, enclosed by a 230mm brick wall, ventilated to the outside, and accessed via a fire door.  Higher buildings will require 2m wide stairs.

9. Shafts: min dimension of 0.6m.

10. Service Floors: should have a minimum clear height of 1.5m.

11. Parking:
In residential buildings, for tenements upto 70 m2 in area, 1 car per tenement, 2 for bigger flats (except in A Ward, where 4 are required).  After this, add 10% for visitors. (50% of spaces can may be 4.5 x 2.3m, the rest not less than 5.5 x 2.5m).

In educational buildings, it is one car per every 35m2 of carpet area of the administrative offices and public services spaces only.


Disclaimer: The above mentioned details are meant to be used for basic guidance only. For taking any decisions with related to actual construction in Mumbai, please consult a professional architect who can give you details with regards to the same on a professional level.
These regulations are updated periodically. Please Consult your licensed architects and permission experts before constructing or planning any construction activity.