Decay of star formation described by the equation (see Eq. (3)) and its posterior distribution. The parameter β₁ depicts the speed at which galaxies quench; a higher value indicates faster quenching and β₂ describes the quenching behaviour and is related to the Kennicutt–Schmidt relation (see Appendix A). The green lines cover 65% and 95% of the total distribution. The large blue dot shows the modelling results for the case where β₂ = 1. The secular evolution values need to be fixed for studying environmental effects. For the fixing we used the values depicted with the black dot.