*Abstract*: Rational ellipticity is a very strong condition on a topological space, which in particular forces it to have "simple topology''. Given its conjectured relation to manifolds with non-negative sectional curvature, a number of previous works has focused on finding geometric criteria that imply rational ellipticity. In this talk, I will describe a new criterion for a Riemannian G-manifold to be rationally elliptic, which generalizes most of the previously known ones. As an application, we will prove that non-negatively curved manifolds with an infinitesimally polar cohomogeneity 3 action must be rationally elliptic. This is joint work with Elahe Khalili Samani.