It has been established experimentally that a zone is formed in an optically denser medium above the interface, which is a major source of the edge light produced due to deflection of light rays in two different directions on both sides of the initial propagation direction. It has been found that the edge light coming from optically denser medium exhibits sharply pronounced asymmetry about the direction of light incidence. An explanation for the asymmetry has been provided. The effect of polarization on the edge light coming from denser medium has been examined. It has been demonstrated experimentally that diffraction zones in denser and less dense media deflect the same light rays in opposite directions.