The density of Mumbai is regulated by one of the lowest, monotonous and inflexible F.S.I. (Floor Space Index, or Floor Area Ratio) measures in the world.  Within the 600 km2 land area, approximately the same area as the city of Chicago, there are only 6 different F.S.I. regulatory values, from 0.5 to 4.0.  In southern Mumbai, where it is most populated, the FSI is constrained at 1.33 with the exception of Bandra-Kurla, a newly established central business district valued at 4.0.  Numeric implication of the FSI rule imposed in 1964 is clearly reflected in the city’s physical skyline.

The near-uniform F.S.I. regulation originally aimed to prevent overcrowding and hoped to create the appearance of a garden city, has failed terribly from that objective.  Instead, the FSI have contributed to the city’s wealth gap due to the artificial shortage of land and inflation of land price.  Spatial consequence of this condition results in 60% of the city’s population not having access to formal housing and lives in approximately 10% of the city’s land in slum areas.  Mumbaikars at or near poverty line constantly confronts those with more affluent means on the territorialization of floor space, very often in extreme close proximity.  Although wealth polarization are well founded in other cities from the global south such as Jakarta, Manila and Hong Kong.  None possesses such vast difference between the two worlds within one spatiality.

This paper aims to investigate Mumbai’s interstitial conditions created by the simultaneously overlapped and juxtaposed worlds.  On the one hand: stable, affluent and institutional with the nimble, impoverished and individualistic on the other.  This hyper overlap of conditions will be examined through the lens of F.S.I. and the peculiar effects it has created.  The significance of this investigation is to provide an alternative frame of reference for reading and evaluating Mumbai by shifting away from the dialectic of the formal versus informal; and towards the interstitial conditions between them resulting from the F.S.I. regulation.  Findings of the research seek to fulfill scholarship currently absent on Mumbai.