Developing a framework for a sustainable city index: A comprehensive approach to urban sustainability

This study aims to develop a Sustainable City Index to assess the sustainability performance of cities. In this context, Istanbul, with its 39 districts of diverse characteristics, has been selected as a pilot case. Although the study focuses on districts, the large population of a single Istanbul district and consistent data accessibility enhance the index's relevance at the urban scale. The study integrates environmental, social, economic, and institutional indicators to establish a comprehensive index for evaluating urban sustainability. Additionally, considering the potential impact of different levels of urbanization on sustainability performance, spatial analyses based on population density and land permeability have been conducted, and the applicability of the developed index has been examined for districts with varying degrees of urban development, including both densely built-up centers and urban peripheral areas. Furthermore, potential limitations in data accessibility have been considered, and reliable, representative indicators have been identified to assess whether it is feasible to develop a core Sustainable City Index. The findings indicate that the developed index not only provides meaningful results in measuring the sustainability performance of a city but also remains applicable to spatial contexts with differing urbanization intensities. Moreover, it demonstrates that sustainability performance can be effectively evaluated using a smaller set of representative indicators. This index serves as a valuable tool for policymakers and urban planners in developing context-specific sustainability strategies while also offering a widely applicable methodology.