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Amid rising mercury, green constructions gain traction

Jun 03, 2024 05:48 AM IST

When it comes to mandates, states have been slow to notify and mandate Union government guidelines such as Energy Conservation Building Code (ECBC)

Construction work in India is back in full swing after a brief lull due to the pandemic, with building sector set to become the world’s third largest — the sectors only in US, China and Japan are larger at present — and with most of the housing stock required for 2030 yet to be built.

The building sector is conventionally considered to be resource-intensive and is held responsible for 40% of carbon emissions worldwide. (Vipin Kumar/HT)
The building sector is conventionally considered to be resource-intensive and is held responsible for 40% of carbon emissions worldwide. (Vipin Kumar/HT)

The building sector is conventionally considered to be resource-intensive and is held responsible for 40% of carbon emissions worldwide due to its heavy reliance on polluting activities such as mining, transportation, and manufacturing of building materials.

In India, the share of carbon emissions is 25%, but the resource extraction rate is close to four times the global average at 1,580 tonnes per acre, against 450 tonnes per acre for the rest of the world, according to Union government estimates in 2019.

With this in mind, many experts believe that a significant push for sustainability should be prioritised, especially in light of India’s net zero emission target by 2070, as made at the United Nations Framework Convention on Climate Change (COP26) in November 2021.

Therefore, sustainability principles across all stages of construction, from initial design to eventual demolition and local sourcing of materials, are necessary, said Sarah Khan, senior associate at the thinktank Center for Study of Science, Technology and Policy.

Similarly, decarbonising the building sector must be approached at different levels—production of materials, transportation of those materials, and site management, said Shashank Bishnoi, professor of civil engineering at IIT Delhi.

Moving beyond conventional material

Two key materials used in conventional construction in India — steel and cement — are both carbon-intensive. “Since the scale is huge, the effect on the environment is too big to ignore. Concrete is the largest material produced in the world. More than half of what we produce is concrete,” Bishnoi said.

He is part of a team of researchers that has developed a low-carbon cement LC3 (limestone calcined clay cement) that can potentially reduce emissions by 40%, compared to most used conventional cement (ordinary Portland cement or OPC).

The application of this cement has taken place in more than 25 projects in India. Notably, the Swiss Agency for Development and Cooperation building in the Swiss Embassy compound in Delhi was built with this cement in November 2019. Following a Bureau of Standards (BSI) certification in 2023, it is being used in both India and abroad at a larger scale.

Vaibhav Rathi, a climate change and circular economy expert, said that just like steel and cement, another ubiquitous building material in India — red clay bricks — is carbon intensive and needs to be avoided. The production of red clay bricks requires high temperatures at kilns, which consumes a significant amount of energy. This energy comes from burning fossil fuels, leading to greenhouse gas emissions. Further, the extraction of clay disturbs local ecosystems and leads to habitat destruction, soil erosion, and loss of biodiversity, he said.

According to Rathi, a much greener alternative — bricks made using fly ash waste from coal power plants — is available in the market and should be the preferred choice as building material. He said that Bihar has taken proactive steps to ensure their adoption, even though the union power ministry has mandated free distribution of fly ash to brick makers within a 300-km radius of power plants. However, according to the central electricity commission (CEC), only 64% of fly ash generated by coal power plants was used by the industry.

Another measure that experts point to in order to reduce environmental stress in the sector is increasing the usage of industrial and construction and demolition (C&D) waste. Traditionally, aluminium and other metals that are used in construction have a functional secondary market, but the rubble left from demolition is often left unused, despite C&D Waste Management Rules, 2016 notified by the Union government.

Rathi said C&D waste can be used as aggregates to make concrete. Even though BIS allows the utilisation of 25% of recycled materials as construction materials, which proves to be cost-effective, there are no laws mandating their use.

He said it is only large builders adopt this stratagem, as it is one of the criteria for green certification of buildings and is incentivised by states.

For example, in Uttar Pradesh, buildings with a four-star rating from GRIHA (Green Rating for Integrated Habitat Assessment, a rating system developed by Teri) are given an additional floor area ratio of 25%. Similar incentives related to additional FSI (Floor Space Index or maximum permissible floor area relative to the plot size) are given by state governments in other states such as Delhi, Chhattisgarh, West Bengal, and Rajasthan.

Mala Singh, co-chairperson of the Confederation of Indian Industries-Indian Green Building Council (CII-IGBC), said a mandate by Sebi for the top 1,000 companies in India to make ESG disclosures also indirectly pushes for green development.

Further, she said, the union environment ministry also fast-tracks environmental clearance for buildings adopting green certifications. “These have led to 11 billion square feet of real estate getting IGBC certifications today, compared to only 20,000 sq feet in 2003,” she said.

Green stratagems slow to catch on

With awareness of green stratagems growing within the building industry, the materials sector has also evolved, with more than 8,000 CII-certified eco-label construction materials readily available in the market.

However, when it comes to mandates, states have been slow to notify and mandate Union government guidelines such as Energy Conservation Building Code (ECBC) for all large commercial, non-residential buildings and Eco-Niwas Samhita (ECBC-R) for residential buildings.

A World Resources Institute study published in January 2024 found that even though 24 states have adopted these codes, their enforcement by state and city authorities needs more rigour.

On this, Vivek Anand, lead architect at Rudrabhishek Enterprises, a consulting firm working on various Union ministry of housing and urban affairs (MoHUA) projects, said more needs to be done to create awareness of reduced life-cycle cost and other benefits of sustainable construction to further the uptake by smaller developers. He advocated for incentivising sustainable practices through tax benefits, subsidies, or certification rewards that can stimulate wider adoption.

Meanwhile, the Central Public Works Department (CPWD), an arm of MoHUA which oversees the construction of central government buildings, has adopted a minimum 3-star GRIHA rating for constructing all government buildings since August 2016. A CPWD spokesperson said an additional set of green criteria will be adopted by the body in the coming months.

Pollution is also caused due to the improper storage of C&D waste and dust control measures within sites. C&D waste, which is mandated to be processed separately, ends up in landfills after getting mixed with municipal waste. While improper storage of sand and cement makes the construction site’s surroundings dusty.

However, a push for embracing relatively modern technologies such as prefabrication, modular and 3D printing presents further opportunities to minimise dust and waste, said Manit Rastogi, founder member of the GRIHA Council and founding partner of the architecture and urban design firm Morphogenesis.

The first such 3D-printed public building in India — the Cambridge Layout post office in Bengaluru — was built in mid-2023 by L&T after the technology was approved by the Building Materials and Technology Promotion Council (BMTPC), an autonomous agency under MoHUA.

Shailesh Agrawal, executive director at BMTPC, said the council in recent years has taken up several initiatives to mainstream upcoming technologies. He cited the six lighthouse projects of 1,000 units each under the Pradhan Mantri Awas Yojana (PMAY)—where six different prefabricated technologies that reduce in-situ dust and pollution to the bare minimum were showcased.

He said BMTPC had been working on several demonstration projects building around 40-50 housing units each in Bihar, Nagaland, Jammu and Kashmir, and Assam among other places where the entire project costs have been borne by the union government.

However, Agarwal noted, the general predisposition towards traditional materials such as cement, concrete, and brick remain the major hindrance. “We had seen the application of bamboo in northeastern states, and it is widely known in the industry about their sustainability characteristics, but there is no real demand in the market,” he said.

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