Extinction index variability with the absolute extinction (A_1.61) for six different regions of the GALACTICNUCLEUS survey (indicated for each panel). The upper blue points and lower green ones indicate the values of α_JH and for each absolute extinction A_1.61, including the statistical uncertainties. Big blue triangles and green squares indicate the average value per region obtained in Table 2. The blue and green crosses indicate the systematic uncertainties due to the ZP computed for each region.