RETHINKING URBAN GROWTH SANJAY PURI ON THE FUTURE OF INDIAN CITIES

Sustainability in architecture has gained significant momentum in recent years. How do you see the industry evolving by 2030?

A: Five years ago, sustainability was barely discussed in real estate. Climate change was a distant thought, and architects focused on maximising commercial feasibility rather than minimising environmental impact. However, over the past two years, the conversation has changed. A growing segment of developers and clients is recognising the long-term benefits of sustainability. Though only about 5% of the industry is seriously committed at present, I anticipate that over 50% will adopt sustainable practices in the coming years. The real challenge lies in reducing the carbon footprint at every stage of construction—from material selection and energy-efficient design to labour-intensive processes. There is an increasing awareness that climate-responsive design is no longer a choice but a necessity.

Many argue that sustainability is still seen as a niche concept in Indian real estate. How can it be made more accessible for mass housing projects?

A: The only way to make sustainability mainstream is through strong regulatory policies. Right now, sustainable design is still optional, and a select few developers and architects have adopted it. This needs to change. For instance, rainwater harvesting was not a mandatory requirement in Mumbai until recently. Imagine if similar government policies mandated solar energy usage in at least 30% of residential buildings or if developers were required to use 20% recycled materials in every project. If these measures were enforced, mass housing projects would be naturally aligned with sustainability goals. Without policy-driven intervention, progress will be slow. Developers will continue prioritising cost-cutting over eco-friendly practices, and sustainable solutions will remain limited to high-end luxury projects.

There is a perception that sustainability and luxury are contradictory. Do you believe the two can co-exist?

A: The notion that luxury and sustainability are inherently contradictory is a widespread misconception. In reality, some of the most exclusive and high-end residences seamlessly integrate eco-conscious design principles, demonstrating that opulence and environmental responsibility can coexist. True luxury is not just about grandeur and excess; it is about creating spaces that offer comfort, longevity, and a harmonious relationship with the surrounding environment. A well-designed home that minimises its ecological footprint while maximising efficiency and aesthetic appeal is, in fact, the pinnacle of modern luxury.

One of the finest examples of this approach is a 36,000-square-foot residence designed in Rajasthan, where summer temperatures can soar beyond 42°C. In conventional thinking, a house of this scale and in such an extreme climate would necessitate high-powered air conditioning systems to maintain a comfortable indoor environment. Instead of relying on artificial cooling, the design prioritised passive climate control strategies that significantly reduced energy consumption while enhancing the home’s overall ambience.

The architectural layout features a courtyard-based design, ensuring that natural air circulation keeps the interiors ventilated and cool throughout the day. Lime-coated roofs reflect heat instead of absorbing it, further lowering the temperature inside the home. Utilising locally sourced materials not only enhances insulation but also minimises the environmental impact associated with transportation and manufacturing, reinforcing sustainability principles without compromising aesthetic refinement. The outcome is a home that remains naturally cool even in the height of summer, eliminating the need for air conditioning and significantly reducing energy consumption.

Indian cities are witnessing unprecedented vertical expansion. How can sustainable principles be incorporated into high-rise architecture?

A: Sustainable high-rise architecture is entirely achievable, but it demands a fundamental shift in approach. One of the most significant missteps in modern Indian urban development is the uncritical adoption of Western architectural trends without accounting for the realities of India’s climate. Many contemporary high-rises, particularly in cities like Mumbai and Bangalore, are designed with expansive glass façades that may look aesthetically striking but are functionally inadequate for tropical conditions.

Buildings with full-glass exteriors absorb and trap excessive heat, creating an indoor environment that is unbearably warm and necessitating continuous air conditioning. This, in turn, leads to significantly higher energy consumption, as occupants are forced to rely on artificial cooling systems throughout the day. Moreover, glass façades often result in glare, making natural daylight a discomfort rather than an asset. Tenants end up keeping blinds drawn, negating the very purpose of having large windows in the first place.

A more effective and sustainable approach to high-rise architecture involves designing buildings that work with, rather than against, their climate. A 21-storey residential project in Udaipur serves as a case study for this philosophy. Instead of an all-glass structure, the design prioritised passive cooling techniques that significantly reduce the need for artificial climate control. The building features large balconies that provide shade and prevent direct sunlight from overheating interior spaces. The strategic orientation of the structure minimises solar exposure during peak hours, ensuring that the building remains naturally cooler. Additionally, cross-ventilation techniques have been integrated into the design, allowing for consistent airflow that eliminates the necessity for excessive cooling.

Even during the peak of summer, these apartments maintain a comfortable indoor temperature without excessive reliance on air conditioning. This project proves that sustainable high-rises are possible and can be implemented on a large scale through intelligent planning. The key lies in moving beyond superficial aesthetics and focusing on practical design solutions that enhance efficiency while maintaining comfort. By prioritising shading, airflow, and climate-responsive design elements, high-rises can be both sustainable and liveable, setting a new benchmark for urban architecture in India.

Traditional Indian homes were naturally climate-responsive. Can we incorporate these principles into contemporary urban design?

A: India’s traditional architecture was inherently sustainable, designed to work in harmony with the climate rather than against it. Homes were built with thick mud walls providing natural insulation, shaded courtyards facilitating passive cooling, and ventilated roofs allowing heat to escape efficiently. These elements ensured interiors remained comfortable despite extreme weather conditions without artificial cooling systems. Unfortunately, the rapid urbanisation of modern India has primarily abandoned these climate-responsive techniques in favour of construction methods driven by speed and cost efficiency. As a result, contemporary urban buildings often prioritise aesthetic trends over environmental adaptability, leading to increased energy consumption and inefficient temperature regulation.

However, advancements in materials and technology now offer an opportunity to reintroduce traditional design principles into modern architecture. Sustainable materials such as Indowood, which is derived from rice husk, provide an eco-friendly alternative to conventional wood, reducing dependency on deforestation while maintaining durability. Foam concrete is another innovative solution—it is lightweight, requires minimal water during production, and offers excellent insulation properties, making it an ideal substitute for traditional concrete in energy-efficient buildings. Similarly, aerated clay blocks outperform standard bricks in terms of thermal efficiency, reducing heat absorption and thereby lowering cooling requirements. The key lies in striking a balance—embracing the wisdom of traditional design while leveraging the advantages of modern innovation to create more sustainable and comfortable living environments.

Mumbai’s real estate landscape has changed dramatically over the years. Has the city’s growth been planned in the right direction?

A: Mumbai’s rapid transformation into a high-density urban hub has not been accompanied by the necessary planning and infrastructure improvements. The city’s real estate expansion has primarily been driven by commercial and residential demand rather than a well-structured urban development strategy. This lack of foresight has resulted in severe infrastructural strain, as new high-rises and commercial complexes emerge without corresponding enhancements to transport, drainage, and civic amenities.

A prime example of this flawed approach is Bandra-Kurla Complex (BKC), which has become one of Mumbai’s most prominent commercial districts. Despite its status as a modern business hub, the area is plagued by inefficient urban design. Most office buildings here feature extensive glass façades, an architectural choice completely unsuitable for Mumbai’s tropical climate. These structures absorb and retain excessive heat, making indoor environments heavily reliant on air conditioning, which, in turn, drives up energy consumption. While the district presents a sleek, modern skyline, it lacks thoughtful planning that prioritises sustainability, pedestrian accessibility, and green spaces.

Beyond the issue of inefficient building design, Mumbai’s redevelopment model itself is deeply flawed. The city’s approach focuses on demolishing and rebuilding individual buildings rather than addressing entire neighbourhoods or districts in a holistic manner. This fragmented method means that while structures are replaced with taller and more modern ones, the surrounding infrastructure remains largely unchanged. Roads remain narrow and congested, drainage systems are outdated and incapable of handling increasing volumes of wastewater, and transport networks fail to keep pace with the swelling population density. As a result, rather than improving liveability, redevelopment often exacerbates existing urban challenges, leading to severe congestion, overburdened public utilities, and a deteriorating quality of life for residents.

A more structured approach, such as the one implemented in Gurgaon, could provide a solution. In Gurgaon, group housing projects are only approved if they span a minimum of 10 acres, ensuring that large-scale developments incorporate essential infrastructure such as green spaces, parking facilities, and efficient stormwater management. This model allows for better-planned urban growth where buildings, roads, and public amenities develop in tandem.

What policy interventions are necessary to improve urban planning in Mumbai and other Indian cities?

A: The biggest issue in Indian urban planning is the lack of cohesive redevelopment policies. Unlike cities such as Singapore, Tokyo, or even Gurgaon, where large-scale planning is implemented, Mumbai’s redevelopment happens in isolated fragments. A policy-driven solution would require that infrastructure improvements be made in parallel whenever a cluster of old buildings is redeveloped. This means expanding roads, integrating sustainable drainage solutions, and ensuring green and open spaces are incorporated into the plan. Without such interventions, redevelopment will continue to overpopulate already strained neighbourhoods without improving quality of life.

The taxation structure also needs reform. Mumbai’s real estate sector faces over 46 premiums before construction approvals are granted. This drives up costs, making housing unaffordable for many. Compared to other cities, where approval processes are more streamlined, Mumbai’s excessive bureaucracy slows development while discouraging sustainable practices.

Another crucial policy shift should focus on mandatory sustainability measures. If the government requires that a certain percentage of all buildings integrate solar energy, rainwater harvesting, and recycled materials, developers will have no choice but to comply. Sustainability should not be left to individual discretion—it must be a regulated requirement.

Looking ahead to the next decade, where do you see Indian cities heading in terms of urban sustainability?

A: If Indian cities continue their current trajectory, they will face severe environmental and infrastructural challenges. Rising urban heat levels, increasing air pollution, and depleting water resources will make it difficult for cities to remain habitable unless sustainability is integrated into development plans. By 2030, urban heat islands will become a significant issue, particularly in metros like Delhi, Mumbai, and Bangalore, where concrete-dense structures absorb and retain excessive heat. Water shortages will worsen, especially in cities that have overexploited groundwater reserves without implementing rainwater harvesting measures. Waste management will also become a critical crisis, with landfills reaching capacity and inadequate recycling infrastructure.

The only way forward is to enforce sustainability through legal mandates. Developers should be required by law to integrate renewable energy, and water conservation should be a standard part of construction approvals. If these measures are not made compulsory, cities will continue to expand without accounting for the rapidly depleting resources. Cities like Ahmedabad and Indore have already started taking progressive steps to manage waste and conserve water, proving that sustainable urban development is possible. However, unless these initiatives are adopted nationwide, we risk creating unsustainable and uninhabitable urban environments.