Colour–colour diagrams for the Clean samples using the NIR photometry data from HAWK-I catalouge (Preibisch et al. 2011a). We divide samples into six groups using MAP estimates: M-type stars (T_eff < 4000 K), K/G-type stars (T_eff ≥ 4000 K), r_veil < 0.1, 0.1 ≤ r_veil < 0.3, and r_veil > 0.3. The colour of each star indicates the corresponding T_eff value. The black dashed lines with a slope of 1.86 indicate the NIR excess selection threshold from Zeidler et al. (2016), where stars located to the right of the dashed line are classified as having NIR excess in IT24. We present the fraction of stars with NIR excess at the upper left corner of each panel (f_NIR).