Fraction of cold molecular gas as a function of the galaxy stellar masses. The colours and shapes of the symbols are the same as in Fig. 7. The dotted line is the fit of the M_star–μ_H2 relation for the PHIBSS2 galaxies at 0.49 < z ≤ 0.6, with its variance being represented by the two dashed lines. The pink outlined green symbols are for our low-μ_H2 galaxies, which are located below the 1 × σ_H2 line of the M_star–μ_H2 relation for the PHIBSS2 field galaxies.