  In equilibrium, the effect of a spatially localised perturbation is typically
confined around the perturbed region. Quite contrary to this, in a
non-equilibrium stationary state often the entire system is affected. This
appears to be a generic feature of non-equilibrium. We study such non-local
response in the stationary state of a lattice gas with a shear drive at the
boundary which keeps the system out of equilibrium. We show that a perturbation
in the form of a localised blockage at the boundary, induces algebraically
decaying density and current profile. In two examples, non-interacting
particles and particles with simple exclusion, we analytically derive the
power-law tail of the profiles.
