Challenges and solutions for achieving carbon neutrality through urban green infrastructure in China's future cities

China has committed to achieving carbon neutrality by the 2060s. In this context, urban green infrastructure (UGI) is increasingly recognised as a nature-based solution with a significant potential for climate change mitigation and adaptation, while also contributing to the broader achievement of sustainable development goals. Although the carbon reduction potential of UGI is been widely acknowledged, several critical gaps remain in understanding its mitigation mechanisms, the integration with carbon qualification methods, the identification of influential factors, and the evaluation of UGI's potential as a mainstream strategy for achieving carbon neutrality. This study systematically reviews evidence from 464 global publications, including 85 focused specifically on China, to address these gaps. We categorise UGI's carbon mitigation mechanisms and align them with the corresponding carbon quantification methods, highlighting the strengths and limitations of each across three primary pathways: carbon sequestration, thermal regulation, and urban agriculture. Furthermore, we identify critical factors influencing carbon mitigation outcomes and assess the methodological trade-offs inherent in the different qualification approaches. The study also explores the current landscape of UGI-related carbon initiatives at multiple governance levels in China and offers recommendations for policy development at national, regional, and local scales. By synthesising scientific evidence with policy analysis, this research provides a foundation for leveraging UGI as an integrated and scalable strategy to support the achievement of carbon neutrality.