Cement and concrete account for around 8% of global CO2 emissions and remain among the most hard-to-abate sectors, alongside steel and chemicals. Demand for these materials is projected to grow substantially over the coming decades, particularly across the Global South, driven by rapid urbanization and infrastructure development. While numerous decarbonization technologies and strategies have emerged and are being implemented, the absence of quantitative, context-specific definitions of low-carbon concrete make it difficult to quantify the extent of decarbonization, especially in developing economies. Using India as an illustrative case, where cement production is projected to grow roughly five-fold by 2070, this perspective examines why low-carbon concrete ratings and definitions applied in the developed world cannot be directly implemented in developing-country contexts. It also proposes a phased strategy towards quantitative definitions for the organized and unorganized concrete sectors. This offers a practical pathway to closing the definitional gap that currently limits the efficacy and accounting of cement and concrete sector decarbonization efforts in the global south.