PBH parameter exclusion plot in the f_PBH − m_PBH plane. We plot the constraint on the monochromatic PBH abundance from the CMB μ-distortion absence (Nakama et al. 2018, green lines) within different non-Gaussianity scenarios (f_NL = 0, 10, ∞ represented by the solid, dashed, and dotted lines, respectively) and the one from the observed CMB angular power spectrum (Serpico et al. 2020, orange line). The shaded regions are excluded, and their colors denote the violated limit (same color scheme as for the lines). The stars and error bars give the results and uncertainty for different values of λ_E (Tab. 1). The dotted red line traces the expected trend for varying λ_E when only an AGN contribution is present.