The need to cut carbon emissions in cities have become more pressing in an age of unparalleled urbanization and climate change. Using both quantitative and qualitative analysis, this study looks at how smart city efforts affect the decrease of carbon emissions. Carbon Reduction Test results and comparative studies show that smart cities with a comprehensive approach—including renewable energy use, energy-efficient buildings, public transportation upgrades, green energy projects, waste management enhancements, and energy-efficient transportation—achieved significant carbon emission reductions. These results demonstrate the transformational potential of smart cities in supporting international sustainability efforts and the efficacy of diverse techniques in reducing the urban carbon footprint.