Desktop-based approaches have been increasingly employed by integrating empirical data which is available (e.g. LULC maps, infrastructure layouts, master plans, socio-demographic census data) to calculate inequality indices. Such indices can be used to compare inter-city equities or identify suitable locations to implement nature-based solutions to reduce inequalities. The Gini coefficient, Theil entropy index, Atkinson index, are typically used to assess income inequalities. In recent years, these indices have been adapted in non-economic fields, such as equities of carbon emissions and supply of urban ES. However, the full extent of applicability to ES equity assessments has not been well-studied. To answer this, we aim to i) examine the inherent properties of each index on empirical ES supply data; ii) assess the applicability of indices on Singapore as a heterogeneous city and; iii) adopt similar methodologies to other cities for equity comparisons.