Development of building stock model for an emerging city in India: Learnings for enabling circular economy in the built environment

This study explores the prospects of urban mining for a steadily developing city “Thane,” located in the Mumbai Metropolitan Region of India, through building material stock accounting (BMSA). A novel bottom-up approach for stock accounting was developed for the cities with limited data availability, through the integration of geodata spatial analysis, archetype identification through statistical modeling, and regional building design assessment for material intensity calculation. This study is the first of its kind in the Indian context and focuses on the stock estimation of the most common building materials: concrete, reinforcement steel, and masonry bricks within the boundaries of a typical Indian urban area. The results showed that the total built-up stock in Thane city in 2018 amounts to 84.7 million metric ton (MT) by weight; concrete 57.7%, bricks 40.4%, steel 1.9%. Such reservoirs of raw material can be harnessed to fulfill the future material requirements of the construction industry through proposed circular economy interventions such as material bank creation, local recycling facilities, and development of a secondary material market. The material stock estimated in this study was 46.1 MT/capita for permanent building dwellers and with potential infrastructural developments underway, urban mining application can be ensured by redefining design and demolition strategies and multi-level collaboration for generating alternative material sources for the construction sector. This work of BMSA intends to provide meaningful insights into exploring the potentials of urban mining and help chart the future roadmaps of sustainable construction in India.