According to a recent study supported by the cement industry, India’s concrete absorbed around 40 million tonnes of carbon dioxide in 2024–2025, largely offsetting emissions from the cement business. According to the National Council for Cement and Building Materials and GCCA India’s assessment, during the most recent fiscal year, concrete in use captured roughly 40.68 million tonnes of carbon dioxide.

Using a cautious international technique tailored to Indian conditions, that absorption was computed against calcination-related emissions of approximately 167.11 million tonnes of carbon dioxide from clinker production.

According to India’s Biennial Update Reports to the UN climate committee, the cement industry in India contributes roughly 6.3% of the nation’s total carbon dioxide emissions, making the findings position carbon uptake by concrete as a quantifiable decarbonisation lever.

India’s official greenhouse gas inventory has not yet included a measurement of this natural absorption process. According to Dr L.P. Singh, director-general of the National Council for Cement and Building Materials, “This report on carbon uptake by concrete quantifies carbon dioxide sequestration through carbon uptake by concrete structures and mortar, partially offsetting cement-related carbon dioxide emissions.”

Future climate reporting and policy frameworks may benefit from the knowledge, he continued. The study found that between 1996 and 2024, concrete in India absorbed an average of 22.45 million tonnes of carbon dioxide annually. Cement production, urbanisation, and infrastructure growth have all contributed to a steady increase in uptake. In 2024–2025, India produced over 453 million tonnes of cement, up from roughly 76 million tonnes in 1996–1997. As the nation’s stock of concrete structures and infrastructure grew, the anticipated yearly carbon intake increased significantly throughout that time.

The investigation solely looked at concrete’s usage phase, which includes structures and operational infrastructure. According to the report, the numbers were purposefully kept conservative by excluding emissions from absorption during demolition, recycling, and later usage. The IVL Environmental Research Institute in Sweden created the Tier 1 technique that was used to produce the results. According to this method, concrete is expected to absorb around 20% of calcination-related emissions throughout the course of its service life, after accounting for India’s 15% mortar use share. Carbonation or recarbonation is the process by which carbon dioxide is organically reabsorbed by concrete. Carbon dioxide from the atmosphere permeates the pores of the concrete and combines with calcium-containing substances that are created when the cement hydrates.

A stable, insoluble substance called calcium carbonate is created as a result of this reaction, and it permanently binds carbon dioxide inside the concrete matrix. Porosity, humidity, temperature, cement mix, and surface exposure are some of the variables that affect the process, which happens gradually over decades.

According to the findings, concrete’s carbonation rates are higher in its early years and decrease with time. Carbon dioxide is absorbed more quickly by exposed surfaces—like walls or crushed concrete—than by coated or sealed buildings. According to the study, additional cementitious materials like fly ash and slag can diminish the potential for total uptake since they contain less clinker, but they also lower the upfront emissions from the manufacture of cement.