  Non-unitary neutrino mixing in the light neutrino sector is a direct
consequence of type-I seesaw neutrino mass models. In these models, light
neutrino mixing is described by a sub-matrix of the full lepton mixing matrix
and, then, it is not unitary in general. In consequence, neutrino oscillations
are characterized by additional parameters, including new sources of CP
violation. Here we perform a combined analysis of short and long-baseline
neutrino oscillation data in this extended mixing scenario. We did not find a
significant deviation from unitary mixing, and the complementary data sets have
been used to constrain the non-unitarity parameters. We have also found that
the T2K and NOvA tension in the determination of the Dirac CP-phase is not
alleviated in the context of non-unitary neutrino mixing.
