  The implications of shearfree condition on instability range of anisotropic
fluid in $f(R,T)$ are studied in this manuscript. A viable $f(R, T)$ model is
chosen to arrive at stability criterion, where $R$ is Ricci scalar and $T$ is
the trace of energy momentum tensor. The evolution of spherical star is
explored by employing perturbation scheme on modified field equations and
contracted Bianchi identities in $f(R, T)$. The effect of imposed shearfree
condition on collapse equation and adiabatic index $\Gamma$ is studied in
Newtonian and post-Newtonian regimes.
