154 ITU‐T's Technical Reports and Specifications Figure 2 – Dimensions of evaluation of SSC Source: FG‐SSC11 Using the evaluation principles explained before, the key performance of SSC can be categorized into six dimensions, each with their respective sub‐dimensions and indicators, as follows: Table 1 – SSC: KPIs, Dimensions and Sub‐dimensions Overview of key performance indicators in smart sustainable cities Dimension label Dimension Sub‐dimension label Sub‐dimension D1 Information and Communication Technology D1.1 Network and access D1.2 Services and Information platforms D1.3 Information security and privacy D1.4 Electromagnetic field D2 Environmental sustainability D2.1 Air quality D2.5 Water, soil and noise D3 Productivity D3.1 Capital investment D3.4 Trade D3.8 Innovation D3.9 Knowledge economy ____________________ 11 ITU FG‐SSC (2014) Technical report on \"Key performance indicators definitions for smart sustainable cities\".