  The first hint of neutrino mass hierarchy is expected to come from the
NO$\nu$A experiment in Fermilab as the present best-fit parameter space i.e.,
normal hierarchy and $\delta_{CP}=-90^\circ$ is the favourable parameter space
for NO$\nu$A where there is no degeneracy. But this situation may change if the
standard three flavour framework is not complete and there is existence of new
physics. In this work we consider the presence of an extra light sterile
neutrino at the eV scale and study the new degeneracies which are absent in the
standard three flavour framework. We also study the effect of these new
degeneracies on the hierarchy measurement of NO$\nu$A.
