The recent announcement regarding the regulation of air conditioner temperatures, implementation of which is still 25 years away, has once again highlighted the urgent need for sustainably built structures. At a time when Mumbai is facing a land crunch and older buildings are undergoing redevelopment one after another, mid-day tried to explore whether the city can adopt a sustainable construction model.
Unfortunately, experts from various fields gave a unanimous answer: “Mumbai cannot have a completely sustainable ecosystem.” But why?
“After modelling the energy released from buildings, vehicles, and human beings, the data suggests that outdoor temperature largely governs indoor temperature. In humid cities like Mumbai, ambient temperatures fluctuate significantly throughout the day, which keeps indoor temperatures slightly higher and affects people’s thermal comfort, the temperature-related comfort a person feels, both outdoors and indoors,” explained Y Nithiyanandam, PhD, professor and head, Geospatial Research Programme, Takshashila Institution.
(From left) Nilanjan Bhowal, principal architect of Design Consortium; Y Nithiyanandam, head, Geospatial Research Programme, Takshashila Institution; Prasanto Roy, owner of first GRIHA-certified green home
“Sustainability demands investment. Today, developers in the city utilise every inch of land. A sustainable project requires ample open space to allow wind flow, which isn’t possible here. Moreover, a truly sustainable high-rise must use renewable energy, locally sourced materials, and minimise reliance on external resources. All this entails significant cost, which developers are unwilling to bear,” he said.
Two major barriers to fully sustainable housing complexes are a lack of awareness among homebuyers and reluctance among developers to invest extra funds. “Constructing a sustainable building can cost 10 to 15 per cent more than a conventional one. If this additional cost is passed on to buyers, especially in an already expensive market like Mumbai, they may lose interest. But if people are made aware that the money they invest upfront will be recovered in a few years through reduced electricity and water bills, they would definitely be more inclined.
“In addition, if developers receive attractive incentives, not just tax benefits or GST rebates, but things like extra FAR (Floor Area Ratio) or FSI (Floor Space Index, it would motivate more of them to adopt green construction,” said Prasanto Roy, owner of India’s first GRIHA-certified green home.
Avoid making things worse
Given the massive redevelopment underway in the city, one of the most crucial issues is how developers manage construction debris. “Debris must be disposed of safely and in a non-hazardous way,” said Nilanjan Bhowal, principal architect of Design Consortium, who designed Roy’s sustainable home.
He added that developers must consider material types and sources in redevelopment. “Glass, for instance, traps heat, raising AC use. Heat-reflective or double-glazed glass reduces energy absorption without increasing outside heat. Avoid mirror-finish reflective glass, as it blocks natural light and increases reliance on artificial lighting, defeating the purpose,” said Bhowal.
Developers speak
“Constructing a 100 per cent eco-friendly structure in Mumbai presents several challenges, including high urban density, regulatory constraints, climate-related issues, and lack of incentives,” explained Niranjan Hiranandani, chairman of NAREDCO.
He added, “Developers can adopt a solution-oriented approach by integrating renewable energy, water recycling systems, energy-efficient designs, and green-certified materials to lower the environmental footprint. Partnering with policymakers to streamline eco-friendly standards could help make Mumbai a model of sustainable urban innovation.”
Hiranandani also acknowledged the practical difficulties, “Balancing sustainability and affordability remains difficult, especially at the planning stage, as both developers and consumers struggle to accept higher price points. To overcome this, developers must invest in innovative construction technologies, explore eco-friendly materials, and push for supportive policies like tax breaks or fast-track approvals, making green housing more feasible.”
