Illustration of our methodology to compute the cluster richness using PSZ2 G032.77+19.69 cluster detected at z = 0.369. The panel presents galaxy counts as a function of redshift for this observed field. The blue line represents the galaxy counts outside 1 Mpc region from the optical centre of the cluster and the dashed blue line represents 1-σ above the latter. The green point shows the galaxy counts (or R₀, i.e., our initial value of the richness) for this particular cluster and its 1-σ error bars. The corrected value of the richness R_cor is then calculated by subtracting from R₀ the background galaxy counts detected at the redshift of the cluster. The complete description of the calculations and discussion of these clusters are presented in Sect. 3.1.