  In an endeavor to explain the light neutrino masses and dark matter (DM)
simultaneously, we study a gauged $U(1)_{\rm B-L}$ extension of the standard
model (SM). The neutrino masses are generated through a variant of type-II
seesaw mechanism in which one of the scalar triplets has a mass in a scale that
is accessible at the present generation colliders. Three SM singlet right
chiral fermions $\chi_{iR}$($i=e,\mu,\tau$) with $\rm B-L$ charges -4, -4, +5
are invoked to cancel the $\rm B-L$ gauge anomalies and the lightest one among
these three fermions becomes a viable DM candidate as their stability is
guaranteed by a remnant $\mathcal Z_2$ symmetry to which $U(1)_{\rm B-L}$ gauge
symmetry gets spontaneously broken. Interestingly in this scenario, the
neutrino mass and the co-annihilation of DM are interlinked through the
breaking of $U(1)_{\rm B-L}$ symmetry. Apart from giving rise to the observed
neutrino mass and dark matter abundance, the model also predicts exciting
signals at the colliders. Especially we see a significant enhancement in the
production cross-section of the TeV scale doubly charged scalar in presence of
the $Z_{\rm BL}$ gauge boson. We discuss all the relevant constraints on model
parameters from observed DM abundance and null detection of DM at direct and
indirect search experiments as well as the constraints on the $\rm B-L$ gauge
boson from recent colliders.
