Top panel: quiescent fraction of cluster galaxies within r <  0.45r₅₀₀ (dark red) and r <  0.7r₅₀₀ (light red) above the mass completeness limit of each cluster as reported in the bottom panel. Error bars account for uncertainties in the quiescent vs. star-forming classification as described in Sect. 5.3. Blue symbols show the quiescent fraction in corresponding photo-z selected control field samples (see Sect. 5.3). Bottom panel: environmental quenching efficiency as derived from cluster and field quiescent fractions in the top panel. Color coding reflects the top panel. In both panels empty triangles show, where applicable, the quiescent fraction and derived quenching efficiency assuming that galaxies lacking a quiescent vs. star-forming classification are all quiescent (rather than all star-forming, see Sect. 5.2, Table 2).