Predicted γ-ray spectra for the different scenarios studied in this work and compared to Tibet ASγ (Amenomori et al. 2021) and Fermi-LAT data in the window |b|< 5°, 50° < l <  200°. The experimental error bars show the 1σ statistical uncertainty of the measurement for CASA-MIA and TIBET data and the systematic plus statistical uncertainty (syst.+stat) for Fermi. The Fermi systematic uncertainties dominate along the full energy range shown, while the systematic error associated with TIBET data in this region is estimated to be around 30% (Amenomori et al. 2009). CASA-MIA (Borione et al. 1998) upper limits in the same region are also reported. The contribution of unresolved sources is not included here.