Density trends in the CECILIA galaxies (red circles) and local EELGs (light-blue squares). Each point represents the simultaneous measurement of n_e[O II] and n_e[S II], and the dotted line reflects equivalent densities. The dark-red and light-blue stars are the average n_e measured in CECILIA and at z = 0, respectively. The top panel plots the histogram distribution of 23 n_e[S II] measurements in the CECILIA sample, where the red bins represent the galaxies with simultaneous n_e[O II]. In agreement with previous findings, the direct measurements of n_e[S II] and n_e[O II] from the CECILIA galaxies indicate that the ISM density at Cosmic Noon is elevated with respect to the n_e measured in the local Universe. Furthermore, n_e[S II] and n_e[O II] show good agreement, as may be expected for two ions primarily originating in the same ionization zone.