A vibrational-rotational operator for the polarizability tensor of asymmetric-top molecules has been obtained by the methods of contact transformations. It has been shown that the rotational transformation gives no contributions being diagonal in the basis of symmetric-top rotational functions. The effect of the rotational dependence of the polarizability operator on the atomic argon pressure induced shift and broadening of rotational-vibrational spectral lines of the v2 band of the H2O molecule has been studied.