  The bulk viscosity ($\zeta$) of the hadronic medium has been estimated within
the ambit of the Hadron Resonance Gas (HRG) model including the Hagedorn
density of states. The HRG thermodynamics within a grand canonical ensemble
provides the mean hadron number as well as its fluctuation. The fluctuation in
the chemical composition of the hadronic medium in the grand canonical ensemble
can result in non-zero divergence of the hadronic fluid flow velocity, allowing
us to estimate the $\zeta$ of the hadronic matter upto a relaxation time. We
study the influence of the hadronic spectrum on $\zeta$ and find its
correlation with the conformal symmetry breaking (CSB) measure, $\epsilon-3P$.
We estimate $\zeta$ along the contours with constant, $S/N_B$ (total
entropy/net baryon number) in the $T-\mu$ plane (temperature-baryonic chemical
potential) for $S/N_B=30, 45$ and 300. We also assess the value of $\zeta$ on
the chemical freezeout curve for various centre of mass energy
($\sqrt{s_{NN}}$) and find that the bulk viscosity to entropy density ratio,
$\zeta/s$ is larger at FAIR than LHC energies.
