Assessing solid waste management effectiveness using the “Zero-waste Index” — Exploration and practice in Chongqing

“Zero-waste City” (ZWC) is an innovative urban development model aimed at reducing solid waste generation, minimizing resource loss, and mitigating environmental impacts. In China, over 100 cities have implemented ZWC initiatives under the 14^th Five-Year Plan, focusing on source reduction and resource recovery across the industrial, agricultural, residential, and construction sectors. However, the absence of quantitative, integrated, and real-time assessment tools has hindered comprehensive evaluation of ZWC progress. To address this gap, this study proposes a “Zero-waste Index” (ZWI) system comprising 15 indicators across seven thematic categories designed to quantify solid waste management performance at the sub-municipal level. The ZWI was empirically applied to 41 districts and counties in Chongqing, a megacity characterized by extensive territorial scope, significant socioeconomic disparities, and uneven levels of administrative infrastructure. Results from two consecutive quarters in 2024 reveal a 12% increase in the citywide average ZWI scores, highlighting strong performance in agricultural and household waste utilization and in energy conservation efforts by public institutions, while also indicating persistent weaknesses in industrial waste management, construction waste compliance, and plastic pollution control, particularly in the Southeastern and Northeastern Areas of Chongqing. ZWI also functions as a governance tool, facilitating feedback-driven performance improvement across districts. Although challenges such as subjective weight allocation and data inconsistencies remain, the ZWI provides a replicable framework for real-time performance tracking and policy feedback, offering valuable insights for other cities seeking to advance “Zero-waste” strategies and improve solid waste management.