  Properties of galaxies depend on their large-scale environment. As the
influence of active galactic nuclei (AGN) in galaxy evolution is becoming more
evident, their large scale environments may help us understand the evolutionary
processes leading to activity. The effect of activity can be seen particularly
by showing if different types of active galaxies are formed by similar
mechanisms. Our aim is to study the supercluster-scale environments of active
galaxies up to redshift 0.4. Our data includes quasars, BL Lac objects, Seyfert
and radio galaxies. We use a three-dimensional low-resolution
luminosity-density field constructed of a sample of luminous red galaxies in
the seventh data release of the Sloan Digital Sky Survey. We calculate the
average density of this field in a volume of a 3\,$h^{-1}$Mpc sphere around
each AGN for estimating the environmental density levels of different types of
AGN. This analysis gives us the distribution of AGN in the global environment
of superclusters, filaments, and voids. Our results show that while radio-quiet
quasars and Seyfert galaxies are mostly located in low-density regions, radio
galaxies have higher environmental densities. BL Lac objects usually have
low-density environments, but some of them are also in very high density
regions. Our results give support to the theory of galaxy evolution where
galaxies are affected by two modes of AGN feedback: quasar mode that turns a
blue star-forming galaxy into a red and dead one, and radio mode that regulates
the growth of massive elliptical galaxies. We conclude that quasars are in
lower density environments than radio galaxies most likely because the galaxies
in rich environments have evolved to a state suitable for radio-loud activity
earlier. Galaxies in poor environment have evolved slower, and are still going
through the earlier quasar mode feedback in galaxy evolution.

Cosmology and Nongalactic Astrophysics