An inclusive model for assessing the sustainability of cities in developing countries – Trinity of Cities' Sustainability from Spatial, Logical and Time Dimensions (TCS-SLTD)

Attaining inclusive, regenerative and sustainable cities for all in the context of unparalleled rates of urbanization, economy-oriented priorities, and chaotic urban development that characterize the developing world is a major challenge. A first step in reaching this goal is to conceptualize an inclusive framework for delineating, assessing and guiding the development of these cities towards sustainability. In this study we outline an inclusive, causal framework for Sustainable Development (SD) assessment, entitled "Trinity of Cities Sustainability from Spatial, Logical and Time Dimensions" (TCS-SLTD). It has been developed for cities in developing countries, and is illustrated using one such city, Xi'an. After reviewing the history and trends of urbanization of cities in Western China, some principles for assessing sustainability of cities in developing countries are suggested, after which the Xi'an case is presented. The urban area of Xi'an has expanded by more than 10 fold during the last quarter century, while arable land has decreased by 39%. In addition to these dramatic changes in land-use, the main axis of urban expansion has shifted from a north-south axial to radial expansion towards all areas around the core city. Over time, urban expansion has followed a "concentrated-deconcentrated- concentrated" trend. Xi'an overall sustainability, as measured by the index we present, has followed an upward - but not monotonic - trend between 1990 and 2010, during which its urbanization rate increased by 30%. On the basis of our multi-dimensional analysis, suggestions are made on how to direct Xi'an toward a more regenerative development path. These include revitalization of the urban system, control of urban form through planning, consulting and informing local communities about sustainable development issues, and achieving efficient functioning and harmonious coordination among different departments and municipal authorities in Xi'an. The TCS-SLTD model, outlined in this study, is a useful tool for guiding the process of Sustainable Development Indicator (SDI) selection, and provides a conceptual framework for holistically assessing the sustainability of city growth and expansion in developing countries. The model can assist urban planners and policy makers in developing countries in the performance of integrated assessments city sustainability, and in the formulation of pragmatic and focused policies to shift cities towards more regenerative and sustainable development trajectories.