Schematic (not to scale) showing the proposed origin of emission of the S-bearing species towards the CMZ of NGC 253 (Sect. 6.3) and summarising the main results for the physical properties (T_gas, n_gas) of the gas emitting the S-bearing species (Sect. 5.2). We illustrate two scenarios, for a giant molecular cloud in the outer (left) CMZ and inner (right) CMZ. The timescale for the shocks induced by star-formation are from Huang et al. (2023). The temperatures and densities reported are averaged over the regions and variations could be present in some of the regions.