  We prove the short-time existence of Ricci flows on complete manifolds with
scalar curvature bounded below uniformly, Ricci curvature bounded below by a
negative quadratic function, and with almost Euclidean isoperimetric inequality
holds locally. In particular, this result applies to manifolds with both Ricci
curvature and injectivity radius bounded from below. We also study the
short-time behaviour of these solutions which may have unbounded curvature at
the initial time, and provide some applications. A key tool is Perelman's
pseudolocality theorem.
