Cement manufacturing is an energy-and carbon-intensive process and a prominent contributor to global anthropogenic greenhouse gases (GHGs). Within emerging economies, this industry's considerable potential to pollute can be exacerbated by outmoded plant or practices, and management's limited capacity to remediate. In this context, the current study analyses the case of Indonesia's leading producer, recording variations in greenhouse gas (GHG) sources to pinpoint opportunities for reduction. Emissions, measured 20% higher than the 2030 global industry target, occur from the calcination process, abetted by fuel combustion. Reductions should be focused on reducing the clinker-to-cement ratio and promoting the uptake of alternative fuels. Avenues lie in increasing the use of clinker substitutes such as fly ash and limestone, and employing fuels derived from waste and biomass. Both sources are abundant in Indonesia. Further declines in GHGs could be achieved through technological innovations such as the upgrading of kilns. The inquiry provides recommendations for emission mitigation in the cement industry not only in Indonesia but also in other developing countries.