The level population of the hydrogen molecule is dramatically altered due to quantum interference, when the molecules are illuminated by two fields (coherent and squeezed) simultaneously. The molecules from the $B{}^{1}{\ensuremath{\Sigma}}_{u}(v=0,j=1)$ is excited stepwise to the level of same symmetry, $B{}^{1}{\ensuremath{\Sigma}}_{u}(v=20,j=1)$ by nondegenerate optical oscillator via an intermediate $E,F{}^{1}{\ensuremath{\Sigma}}_{g}(v=8,j=0),$ and directly by a two-photon transition by a
CO2 laser. The population of the states are also affected by the correlation developed between the two modes of the squeezed field. The correlation and the quantum interference jointly affect the molecules in such a way that the inversion of population occurs periodically. This feature can further be used for studying lasing and other important optical activities.