  Principle of Equivalence makes effects of classical gravity vanish in local
inertial frames. What role does the Principle of Equivalence play as regards
quantum gravitational effects in the local inertial frames? I address this
question here from a specific perspective. At mesoscopic scales close to, but
somewhat larger than, Planck length one could describe quantum spacetime and
matter in terms of an effective geometry. The key feature of such an effective
quantum geometry is the existence of a zero-point-length. When we proceed from
quantum geometry to quantum matter, the zero-point-length will introduce
corrections in the propagator for matter fields in a specific manner. On the
other hand, one cannot ignore the self-gravity of matter fields at the
mesoscopic scales and this will also modify the form of the propagator.
Consistency demands that, these two modifications - coming from two different
directions - are the same. I show that this non-trivial demand is actually
satisfied. Surprisingly, the Principle of Equivalence, operating at sub-Planck
scales, ensures this consistency in a subtle manner.
