Urban Density, FSI, and the Quest for Sustainable Indian Cities

URBAN DENSITY, the concentration of people within a specific urban area, is becoming a palpable concern, especially in countries like India where rapid urbanisation and population growth are intertwined

- Bibek Debroy

India’s metropolitan areas, like Mumbai and Delhi, are emblematic of this swelling issue. Prominent scholars such as Edward Glaeser, in his influential book Triumph of the City, have accentuated the pros and cons of urban density. He argues that while density can foster innovation, collaboration, and economic growth, it can also strain infrastructure, environment, and most crucially, housing. This is palpably depicted in movies like Gully Boy, where the protagonist’s life is significantly shaped by the cramped and constrained environment of Mumbai’s slums. The challenges brought on by urban density have invariably led to a serious re-evaluation of India’s urban planning policies.

Specifically, housing constraints have become pronounced because of strict regulations tied to the Floor Space Index (FSI) and the Floor Area Ratio (FAR). Floor Space Index denotes the ratio achieved by dividing the total Built-Up Area (BUA) of every level by the plot area. To illustrate, an FSI of 1 on a plot of 100 sqm means 100 sqm of BUA. Similarly, FAR is a concept akin to FSI. An FSI value of 1 can equivalently be expressed as 100 per cent FAR. Typically, the building envelope is regulated by the Development Control Regulations (DCR) of a city, dictating the FSI, the maximum extent of ground the building can cover, the maximum height or number of floors permissible, required building setbacks and margins, mandated open spaces, minimum parking provisions, among other specifications.