This paper delves into the interrelationships between urban spatial characteristics and mechanisms. It further proposes a framework for establishing a comprehensive assessment index system for urban spaces with multiscale, spatial form, and spatial diversity as the main attributes. This framework provides a methodology and toolset for the precise identification of problems in the area of living environment. In addition to considering the three basic spatial attributes, the setting of specific indicators needs to address the following requirements: firstly, clarifying the three major subsystem groups corresponding to the indicators—material environment, ecosystem services, and socio-economic aspects—to establish relationships with the basic attributes of urban spaces in subsequent diagnostic stages; secondly, considering the long-term influencing factors and short-term disturbances from human activities in determining the proportional relationships of these indicators scientifically; thirdly, taking into account the regional factors' impact on the threshold values of the index system standards. Building on the comprehensive assessment index framework, this paper proposes a toolset for problem diagnosis for urban spatial issues, encompassing a multi-scale interactive indicator analysis method, a multi-index correlation analysis method involving spatial form, and a multidimensional clustering approach tailored to spatial variations. This research identifies key thresholds influencing urban sustainable development through extensive statistical assessments of indicator values about large samples of micro-units.

Urban regeneration has increasingly become a pivotal strategy for fostering high-quality urban development. However, when applied to historic urban areas, this approach encounters significant complexities due to intricate ownership structures, diverse resident compositions, heritage conservation requirements, and land use regulations. These challenges often result in difficulties and delays in project implementation. This study investigates the renewal practices in Xiaoxihu, Nanjing, employing the theory of "Rescaling" to examine the innovative strategies implemented by local governments. It explores how these approaches influence the restructuring of social relations among various stakeholders through spatial processes. The systematic application of rescaling strategies provides a means to address persistent challenges in renewing China's deteriorated urban communities, including fragmented property rights, difficulties in spatial function integration, and challenges in achieving spatial de-densification. Furthermore, the study offers theoretical insights and practical guidance on mitigating adverse effects associated with growth-oriented urban development, such as the homogenization of urban functions, the excessive commodification of real estate, and increased social tensions.

In the context of China's urban stock renewal, the implementation of micro-renewal in old communities is of strategic importance for the high-quality development of cities and the modernisation of the country's governance capacity. In the context of China's urban stock renewal, the implementation of micro-regeneration in old communities is of strategic importance for the high-quality development of cities and the modernisation of national governance capacity. By exploring the localisation of polycentric governance theory, this paper analyses polycentric governance in the Chinese context, and selects a key micro-renewal project in Qinhuai district, Nanjing as the research object, to explore the multi-party governance mechanism of micro-regeneration in China's aging communities. The study finds that the multi-party governance mechanism is a collaborative renewal mechanism in which multiple actors, including the district government, district state-owned enterprises, planning teams, community grassroots organisations, and residents, participate in a clear division of roles and networked interactions in order to respect residents' property rights and wishes. Among them, the transformation of the government's decentralised role and the effective integration of social forces are the key factors contributing to the construction of the mechanism of multi-party co-regulation; the interactive relationship of the multiple subjects changes continuously with the advancement of the renewal stage; and the establishment of a platform for effective communication and rational interaction among the various subjects is the key to promoting the sustainable development of micro-renewal of the old community, which is currently still in the mode of an external impetus. At present, community micro-renewal in Qinhuai district is still in a mode of external driving force; micro-renewal can create sustainable production benefits for the physical space, social space, economic development, and historical resources of the old community.

Housing, where urban regeneration occurs most frequently, is a valuable spatial resource closely linked to residents. However, massive old and dilapidated communities are trapped in a dual plight of functional decline and value loss due to the absence of formal operation. Qualitative methods are used in this paper to investigate the governance practice of 'Property City' in Tangjiadun subdistrict, Wuhan, which achieved the long-term operation through an integrated approach. The study found that: (1) The multi-stage public-private partnership formed the collaborative governance. (2) The case communities is embedded in integrated governance through horizontal and hierarchical rescaling of operation responsibilities. (3) The case balanced the funds and established an affordable, micro-profitable and sustainable operation mechanism based on the operation of the public assets. The study improves the full life-cycle analysis framework of urban redevelopment and reveals the indispensable role of operation for private property in urban regeneration. Operation mechanisms urgently need to be established in old and dilapidated communities to preserve and increase the value of housing while reducing the frequency and financial burden of urban regeneration.