Ahmedabad: By 2050, five out of every six homes in Ahmedabad will be highrise flats, according to a study. Ahmedabad needs 3.1 million new homes in the next 25 years.Building them — at the height, density, and pace the city is currently planning — will consume 30.2 million tonnes of cement and 13.3 million tonnes of steel between 2031 and 2050.Construction at that scale will generate carbon emissions that researchers warn could consume a disproportionate share of climate headroom.That vertical shift will be largely driven by land scarcity and rising FSI limits, according to a recent study.The study is titled “Assessing strategies to decarbonise embodied carbon impacts of residential buildings in Indian cities: Case of Ahmedabad”.It was published in Environmental Research: Infrastructure and Sustainability.The city’s population is expected to climb from 7.1 million (2015 base) to 12.4 million by 2050, according to the study’s authors, Chaitali Trivedi and Minal Pathak of Ahmedabad University, and Subash Dhar of UNEP Copenhagen Climate Centre.The 3.1 million new residential units are expected to come up across the 1,866 square kilometre jurisdiction of Ahmedabad Urban Development Authority (AUDA).Land scarcity has pushed planners to raise the permissible Floor Space Index (FSI) — the ratio of total floor area to plot size — driving a dramatic shift in housing type.Flats made up 51% of housing stock in 2015; by 2050, they will constitute 83%, the study says. Under the current Gujarat Comprehensive Development Control Regulations (GDCR), buildings can rise to 23 floors. Researchers project that by 2050, up to 20% of affordable and 15% of luxury flats will rise to 50 floors.In this building boom, cement alone will generate 102.2 million tonnes of cumulative carbon emissions, double the 2015 baseline. Steel emissions are projected to climb 1.8-fold to 52.7 million tonnes.For now, Ahmedabad’s buildings are being demolished and rebuilt far earlier than their design life warrants. “Buildings are generally demolished early for newer construction, much sooner than their actual lifespan,” the study notes, putting the average building lifespan at just 45 years.Highrise buildings consume exponentially more cement and steel per square metre than mid-rise construction. Moreover, Ahmedabad’s construction and demolition waste recycling has effectively collapsed.AMC collects only 1,000 tonnes per day of such waste — one-fourth of the city’s total construction debris — while the remaining three-quarters is lost to informal markets.“Waste collectors earn from landfilling, which discourages them from dumping waste at designated plots,” the authors write. National and state codes, including the GDCR, impose no regulations requiring recycled materials in new construction.
