  We study the Distant Red Galaxy (DRG, J-K_s > 2.3) neighbour population of
Quasi Stellar Objects (QSOs) selected from the Sloan Digital Sky Survey (SDSS)
in the redshift range 1 < z < 2. We perform a similar analysis for optically
obscured AGNs (i.e. with a limiting magnitude I > 24) detected in the
mid-infrared (24 $\mu$m) with the Spitzer Space Telescope and a mean redshift
$z\sim 2.2$ in the Flamingos Extragalactic Survey (FLAMEX). Both QSOs and
obscured AGN target samples cover 4.7 deg$^2$ in the same region of the sky. We
find a significant difference in the environment of these two target samples.
Neighbouring galaxies close to QSOs tend to be bluer than galaxies in optically
obscured source environments. We also present results on the cross-correlation
function of DRGs around QSOs and optically faint mid-infrared sources.
  The corresponding correlation length obtained for the QSO sample targets is
$r_0$=$5.4\pm1.6$
  Mpc h$^{-1}$ and a slope of $\gamma$=$1.94\pm0.10$ . For the optically
obscured galaxy sample we find $r_0$=$8.9\pm1.4$ Mpc h$^{-1}$ and a slope of
$\gamma$=$2.27\pm0.20$.
  These results indicate that optically faint obscured sources are located in
denser environment of evolved red galaxies compare to QSOs.
