# Sustainability Assessment on an Urban Scale: Context, Challenges, and Most Relevant Indicators
## 3 Results and Discussion Regarding the Selected Indicators within the Potential Categories
### Land Use and Infrastructure  
This category focuses on analysing the issues related to the land use and infrastructure of the neighbourhoods. As presented in Figure 8, it is assessed through five indicators. The efficient use of urban land is a predominant issue promoted by the studied sustainability assessment tools. Land is a vital yet limited resource. Therefore, managing urban lands to meet the requirements of an expanding urban population is seen as one of the key challenges in achieving an economically efficient, socially equitable, and environmentally safe society [54]. A high-density urban form preserves lands and protects the surrounding natural environment, improving the service provided for the municipality and establishing economies of scale. SDG 11.3.1 highlighted the observation of the land consumption rate to the population growth rate, and ISO 37120 has promoted assessing the built-up density. Urban densification is used in many European urban planning initiatives to encourage the development of the compact city concept, which shares resources and infrastructure to achieve a maximum efficiency while reducing the need for daily mobility [55]. Furthermore, the European Commission promotes the urban densification in the form of infill developments or the reuse of urban land as an emphasized policy that aims to encourage efficient urban structures that are economically sustainable [56]. This strategy is frequently considered against urban sprawl. The essential indicators, which are used to assess how optimized the project is regarding land use and infrastructures, are presented in Figure 8:  
Use the natural potential of land: This indicator is intended to promote land use pattern optimization, which can minimise erosion, protect habitats, and ease the stress on natural water systems by conserving the natural potential of land, such as through preserving steep slopes in a natural and vegetated state [57]. However, the land use regime must be established in the territorial planning instruments, which define the appropriate land classification and qualification. This indicator is covered by SBTool\({}^{\text{PT}}\)_Urban (2018), BREEAM-C (2012), and LEED-ND (2018).  
Densification, and flexibility of land use: The concept for this indicator comprises the densification of existing urban infrastructures and promotes the diversity of uses. These issues are promoted through separated indicators by SNTool (2020) and BREEAM-C (2012) but developed in a combined form in SBTool\({}^{\text{PT}}\)_Urban (2018). The study proposed a combined form of the indicator due to the close relationship between the two criteria. Land densification is defined as the land development that makes maximum use of the existing infrastructure rather than developing on undeveloped land, and recycling is defined as the reuse of abandoned, unused, or underutilized land for redevelopment [58]. Additionally, providing access to a range of land uses and mixed-use development will reduce transportation distances and dependence on cars, which encourages daily walking, biking, and public transportation, leading to car-free living [57].  
Reuse of urban land: This indicator aims to promote the reuse of previously built land areas by enhancing the rehabilitation of contaminated lands and determining the lands that should remain undeveloped due to their ecological or agricultural values. This indicator is addressed by SBTool\({}^{\text{PT}}\)_Urban (2018), SNTool (2020), BREEAM-C (2012), LEED ND (2018), and supported by SDGs.  
Reuse buildings and infrastructure: The objective of this indicator is to promote the reuse or rehabilitation of existing buildings and infrastructures where possible, to extend the life cycle of buildings and conserve resources, reduce waste, and mitigate environmental harm from new building materials manufacturing and transportation. This indicator is covered by SBTool\({}^{\text{PT}}\)_Urban (2018), BREEAM-C (2012), and LEED-ND (2018).