The range of UV light, which causes maximum skin damage, is:

The biologically most active pa of the solar spectrum is UVB (290 -320 nm) since it is primarily responsible for the induction of inflammation, carcinogenesis and immunosuppression. UV-B - (wavelength 290 and 320 nm) most efficient in producing redness or erythema in human skin and thus is some- times known as the "sunburn spectrum." UV-A (wavelength 320 and 400 nm) is ~1000-fold less efficient in producing skin redness than is UV-B.