Density, Intensification and Urban Redevelopment: The Metabolism of Mumbai

Abstract

Increased density has been widely accepted as a requirement for a sustainable city. Most research on the subject has promoted urban compaction without consideration to constrained resources for the operation of a city. This research challenges the conventional views that increased intensification of cities results in increased sustainability and questions the limits to intensification through its analysis of Mumbai as a case study. Mumbai is the world’s densest city. However, Government policy, influenced by Western models of intensification, is to further increase the density of Mumbai by demolishing medium-rise housing in favour of tower blocks; a process known as ‘vertical with a vengeance’. The claim is that it will make Mumbai a more sustainable and ‘world-class’ city. Increasing the population density has significant implications for the input of resources and the output of wastes for the City’s operation. This thesis reviews the resources currently available to the City and identifies the finite limitations of the hinterland. In order to measure the environmental and resource impact of increased density, the ‘extended urban metabolism’ model is employed to compare the existing and proposed developments. A detailed case study of a proposed new development has been conducted at the neighbourhood scale. The results are then extrapolated to the areas of the Island City proposed for redevelopment. The results indicate that intensification policy would result in 1677 new 40-storey tower blocks, 51,780 additional car parking, a reduction in open space, a new 100 MW power station, a new 100 million litres per day dam to supply water, 160 million litres per day of sewage to be processed, 3570 tons per day of CO2 production and many more adverse impacts. All this will be added to a City that, due to inadequate resources and difficult geography, already systematically rations electricity by blackouts, rations water to a few hours per day, and where 80% of sewage is untreated and washes up on the shoreline. The conclusions are that increased density by a more compact and vertical city is neither sustainable nor resilient. Mumbai provides a useful metaphor for other cities since, ultimately, the great majority of them continue to grow and will eventually outstrip the capacity of their hinterlands.