  We consider behavior of equatorial geodesics with the negative energy in the
ergoregion of a generic rotating "dirty" (surrounded by matter) black hole. It
is shown that under very simple and generic conditions on the metric
coefficients, there are no such circular orbits. This entails that such
geodesic must originate and terminate under the event horizon. These results
generalize the observation made for the Kerr metric in A. A. Grib, Yu. V.
Pavlov, and V. D. Vertogradov, Mod. Phys. Lett. 29, 1450110 (2014)
[arXiv:1304.7360].
