Surviving fraction of proton and nuclei EAS in Tibet ASγ experiment after γ-ray-like event selection (Amenomori et al. 2021). The dashed black line shows the upper limit on the total number of surviving γ-ray-like events in the |b|> 20° region. The blue line shows the efficiency of the selection of the γ-ray EAS. For comparison, grey dashed and dotted lines show the efficiencies of the suppression of the hadronic EAS background in HAWC (Abeysekara et al. 2017b) and LHAASO (Wu et al. 2019).