Sustainable Finance for a Zero-Waste Circular Economy in Nairobi County: A Framework for Plastic Solid Waste Quantification, Climate Change Mitigation, and Inclusive Livelihood Transformation

The findings of this study demonstrate that the global increase in plastic solid waste (PSW) has created interconnected environmental, economic, climate, and social challenges, particularly in rapidly urbanizing cities of developing countries. The study developed a Sustainable Finance for Zero-Waste Circular Economy (SF-ZWCE) framework, using global evidence on circular economy, sustainable finance, climate mitigation, and waste management, complemented by empirical evidence from Nairobi County, Kenya. The findings indicate that waste prevention, reuse, repair, source segregation, recycling, composting, anaerobic digestion, and integration of informal waste workers provide greater potential for resource conservation, greenhouse-gas reduction, employment creation, and inclusive economic development than predominantly disposal-oriented systems and Waste-to-Energy incineration. Evidence from Nairobi further shows substantial gaps between plastic waste generation, collection, recovery, financing, and productive reintegration into value chains. The study identifies inadequate financing, infrastructure, governance, data systems, market development, and policy coordination as major barriers to circular transition. The findings further demonstrate that sustainable finance can serve as a transformative mechanism by directing capital toward prevention, material recovery, recycling infrastructure, circular enterprises, climate-aligned technologies, and inclusive livelihood systems. The SF-ZWCE framework advances existing circular-economy approaches by connecting global material-flow challenges with investment decisions, climate outcomes, and livelihood transformation. The study concludes that integrating waste quantification, sustainable finance, and social inclusion can accelerate zero-waste transitions and provide a transferable model for Nairobi and other rapidly urbanizing cities globally.