Left: rest-frame UVJ diagram of protocluster members. The colour selection function is shown in black lines. Identified quiescent galaxies are marked with a star. The sSFRs of the galaxies is coded in colour. The cross in the bottom right corner shows the average uncertainty Right: colour-magnitude diagram of quiescent (red stars) and star-forming (blue dots) members. The background hexagons show the density of field galaxies. Overlaid is a linear fit to the quiescent galaxies (black dashed) and the scatter (gray dot-dashed), with the slope and intercept at M_F200W = 21 shown in text. The observational depth is shown with a gray dotted line.