India’s ambition to become a developed economy by 2047 and achieve net-zero emissions by 2070 brings the construction sector into sharp focus. Cement, one of the most widely used materials in construction, remains a major part of that challenge.
Construction, which relies heavily on cement and steel, contributes an estimated 35% to 40% of global greenhouse gas emissions. A significant share of these emissions comes from the energy-intensive processes required to produce construction materials. Cement, however, presents an additional challenge because carbon dioxide is released not only from fuel consumption but also during the chemical process of converting limestone into clinker.
For India, the issue is particularly important. The country is the world’s second-largest cement producer after China and accounts for around 13% of global annual cement production. Its cement industry comprises 333 manufacturing units, including 159 integrated large cement plants, 116 grinding units, 62 mini cement plants and five clinkerisation units.
India produces around 391 million tonnes of cement, generating approximately 246 million tonnes of CO2 equivalent emissions. This is estimated to account for around 6% of the country’s greenhouse gas emissions.
Why cement is difficult to decarbonise
The production process itself explains why cutting emissions from cement is particularly challenging.
Limestone is the primary raw material. After extraction, it is mixed with clay and heated to temperatures of around 1,450°C. This process, known as calcination, is highly energy intensive. The material produces clinker, which is subsequently crushed into powder and blended with gypsum and other materials to make different types of cement.
Around 35% to 40% of emissions from cement-making are linked to the heating process, while the chemical breakdown of limestone also releases carbon dioxide.
This means simply replacing coal and other conventional fuels with cleaner energy sources will not eliminate cement’s emissions entirely. The chemical reaction itself generates carbon dioxide, making technological intervention necessary alongside cleaner energy.
Alternatives can reduce the sector’s footprint
Several measures could help reduce emissions without abandoning cement as a core construction material.
One option is to increase the use of refuse-derived fuel, or RDF, made from processed combustible waste. It can replace coal and petroleum coke in cement kilns. NITI Aayog has recommended achieving a 20% thermal substitution rate by 2030, which could potentially reduce emissions by around 80 million tonnes of CO2 equivalent cumulatively.
Reducing the amount of clinker used in cement is another important route. Industrial by-products such as fly ash and blast-furnace slag can replace a portion of clinker. The International Energy Agency estimates that replacing one tonne of clinker can avoid approximately 0.83 tonnes of CO2 emissions.
Blended cements such as Portland Pozzolana Cement and Portland Slag Cement already use lower clinker content than Ordinary Portland Cement, offering another pathway towards lower-carbon construction.
Carbon capture, utilisation and storage could also play a role, particularly for emissions that cannot be eliminated through fuel switching or efficiency improvements.
Adoption remains a challenge
The transition, however, is not straightforward. Builders and contractors have long relied on conventional cement, particularly Ordinary Portland Cement, because of its established standards, availability and familiar performance characteristics. Some blended cements can also take longer to develop strength, creating concerns about construction timelines and structural performance.
The availability of alternative fuels presents another hurdle. Poor segregation of municipal waste can limit both the quantity and quality of RDF available to cement plants.
There are also limits to how much clinker or conventional fuel can be substituted. Excessive replacement can affect cement performance depending on the materials and manufacturing process, making compliance with technical and safety standards essential.
Traditional building materials and alternative binders face a further disadvantage because they do not yet have the same scale of manufacturing, standardisation and supply networks as conventional cement.
Building the market for greener cement
Policy and procurement could play an important role in changing this equation. Greater use of certified low-carbon cement in public infrastructure projects could create demand and encourage manufacturers to expand production.
Better waste segregation and processing would strengthen the supply chain for RDF, while research investment could accelerate the development of carbon capture technologies, alternative binders and energy-efficient kilns.
The construction industry will also need to adapt. Architects, engineers and developers can explore alternative materials and construction methods where they meet performance and safety requirements.
India’s cement sector is therefore facing a difficult balancing act. The country needs large-scale construction to support urbanisation and economic development, while simultaneously reducing the emissions associated with that growth. Decarbonising cement will require changes across manufacturing, waste management, procurement, technology and construction practices.
For India’s 2070 net-zero target, making cement cleaner is not simply an environmental priority. It is becoming a central part of how the country builds its next phase of economic growth.
