Summary
India aims to be a developed economy by 2047 and a net-zero emitter by 2070, but cement stands in the way of both goals. Cement accounts for 7 to 11% of global greenhouse gas emissions, nearly double the share of aviation.
Heating kilns to around 1,450 degrees Celsius produces 35 to 40% of the industry's emissions. The rest comes from calcination, the chemical breakdown of limestone that forms clinker. India currently emits 0.62 tonnes of CO2 per tonne of cement and a TERI-GCCA roadmap targets 0.56 by 2030 and 0.51 by 2047.
The same roadmap projects production rising from 334 million tonnes in 2019-20 to 1,546 million tonnes by 2070. NITI Aayog recommends a 20% thermal substitution rate using refuse-derived fuel by 2030 and further reductions in India's clinker-to-cement ratio of about 67.5%.
Experts also point to green public procurement, regional building practices and, eventually, carbon capture.
WHY IT MATTERS FOR UPSC & STATE PCS
A science feature in The Hindu brings together roadmaps from NITI Aayog and TERI with the Global Cement and Concrete Association to examine how India's cement sector can reach net zero. The roadmaps propose lower emission intensity, refuse-derived fuel, clinker substitution and carbon capture.
The piece also notes that most cement emissions come from the chemistry of limestone rather than from fuel. Researchers from CSTEP, NICMAR and Vishwakarma University discuss demand-side measures and traditional alternatives such as Kath Kuni construction.
Standard News
The Intensity Target Falls While Total Emissions Rise: Cement's Arithmetic Problem Start with the
commitment. The TERI-GCCA roadmap aims to cut India's cement emissions from 0.62 to 0.56 tonnes of CO2 per tonne of cement by 2030 and to 0.51 by 2047. That is an 18% improvement in intensity. Now the data. The same roadmap projects production rising from 334 million tonnes (2019-20) to 1,546 million tonnes by 2070, more than four and a half times today's output. Run the numbers:
- Today: 334 Mt × 0.62 ≈ 207 Mt of CO2
- 2070, even at the 0.51 target: 1,546 Mt × 0.51 ≈ 788 Mt of CO2 The target was cleaner cement; the data shows almost four times the emissions. An intensity target can be met in full while the sector moves further from net zero every year. For a 2070 net-zero pledge, the figure that matters is total emissions and on the current path that figure keeps rising.
Why Clean Power Alone Cannot Close the Gap Heating a
kiln to around 1,450°C causes only 35 to 40% of cement emissions. The rest comes from calcination: limestone (calcium carbonate) breaks down into lime and CO2. That carbon is part of the rock and is released by the reaction itself.
Switch every kiln to renewable electricity and the larger share of emissions remains. This is why cement is called hard-to-abate. The problem is the chemistry of the product, not the fuel that heats it.
The Levers That Buy Time and Their Limits -
Clinker substitution: blending fly ash or slag in place of clinker avoids about 0.83 tonnes of CO2 for every tonne of clinker replaced. India's ratio of about 67.5% is already better than the global 77%. In practice, however, the average substitution cannot go much beyond 40% without affecting structural integrity.
- Refuse-derived fuel (RDF): NITI Aayog's target of 20% thermal substitution by 2030 would save about 80 million tonnes of CO2 equivalent over time. But RDF needs municipal waste segregated at source, which is a municipal responsibility, not a cement-industry one.
- Green public procurement: builders prefer OPC because it gains strength in about a week, against roughly twice as long for blended cements. Government buying of blended cement in the early years can create the demand the private market is not yet providing. All three reduce emissions per tonne. None of them removes the chemical carbon.
The weak link is not ambition but measurement. India's roadmaps track tonnes of CO2 per tonne of cement, while net zero is judged by total tonnes emitted. Seeing that difference is what turns a description of cement into an analysis of it.
Quick Facts
Key numbers & takeaways — revise these first
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India's targets: developed economy by 2047, net-zero emissions by 2070 Cement's share of global greenhouse gas emissions: 7 to 11%, nearly double aviation Construction materials (steel, cement and others): 35 to 40% of global greenhouse gas emissions Kiln temperature: around 1,450 degrees Celsius Heating share of cement emissions: 35 to 40%; the remainder comes from the chemical breakdown of limestone Clinker's share of emissions: 53 to 65% India's current emission intensity: 0.62 tonnes of CO2 per tonne of cement TERI-GCCA roadmap targets: 0.56 tonnes by 2030 and 0.51 tonnes by 2047 Projected production: 334 million tonnes in 2019-20 rising to 1,546 million tonnes by 2070 India's clinker-to-cement ratio: about 67.5%, against a global average of 77% NITI Aayog: 20% thermal substitution from refuse-derived fuel by 2030, a cumulative reduction of about 80 million tonnes of CO2 equivalent IEA estimate: replacing one tonne of clinker avoids 0.83 tonnes of CO2 Practical ceiling on average clinker substitution: about 40% Clinker share by cement type: OPC over 95%, Portland pozzolana cement 65 to 80%, Portland slag cement 35 to 64% Portland cement was patented in Britain in 1824 by Joseph Aspdin Kath Kuni: a cement-free, earthquake-resistant building style from Himachal Pradesh
Connect the dots for your UPSC preparation.
Standard news covers the event. Log in to read our comprehensive analysis and uncover the hidden constitutional, structural, and ethical dimensions of this topic:
The full arithmetic of why an 18% intensity cut still leaves the sector at roughly four times today's emissions by 2070
The three separate bottlenecks behind the levers: municipal waste segregation for RDF, builder preference for OPC and the absence of any carbon capture cost or capacity figures in India's roadmaps
Why regional practices such as Kath Kuni, rammed earth and compressed earth blocks reduce cement demand where they suit the site but cannot replace concrete in a ten-storey building
A short-term and long-term way forward linking green procurement, the Carbon Credit Trading Scheme and CCUS to a target based on total emissions
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