CMDs of the final calibrated reddening-corrected photometry for NGC 6822, after removal of extended background galaxies, bright MW contaminants and faint Galactic M dwarf stars. Left panel: I_E versus I_E - H_E . The main stellar evolutionary sequences are indicated: the blue plume (BP), populated by massive MS and post-MS stars in the hot core helium-burning phase (ages ≲ 100 Myr); RSGs with ages from about 20Myr to 50 Myr; bright and red AGB stars with ages from 0.1 to 2 Gyr; red giant branch (RGB) stars, with ages older than 1-2 Gyr; the red clump (RC) of low-mass stars in the core-helium burning phase; and the AGB bump (AGBb). The blue, green, and red polygons, driven by the comparison with stellar evolutionary models, indicate the selection regions used to create the star count maps in Sect. 5.5. as indicated in the legend. Middle: I_E versus I_E - H_E (same as left panel) with superimposed PARSEC stellar isochrones for different ages (10 Myr to 10 Gyr) and for two metallicity values, Z = 0.006 and 0.001 (40% and 6% solar, respectively.). Right: J_E versus Y_E - H_E. In this diagram, the oxygen-rich and the carbon-rich AGB stars (O-AGB and C-AGB) appear well separated and define vertical and horizontal sequences, respectively.