An index providing measurements of ultraviolet (UV) ray intensity is to be issued each day by the Hong Kong Observatory beginning on April 1 to help people avoid skin and eye damage through exposure to strong sunlight. The five-level guide will be included in hourly weather reports broadcast on radio and television, Observatory director Dr Lam Hung-kwan said. Dr Lam said that overexposure to UV radiation from the sun could lead to skin conditions such as burns and, depending on a person's skin colour, in some cases cancer, as well as corneal cataracts. The index will list the strength of the radiation on a scale of one to 10. 'If the index is high, one should cover up sufficiently to avoid exposure, and in case of swimming, he or she should apply suntan lotion more frequently,' the Observatory director said. An ultraviolet sensor has been in place at the King's Park Meteorological Station since October. The index is now available on the Hong Kong Observatory Web site. But because of an increase in public demand for information, the Observatory has decided to give the measurement of ultraviolet rays wider exposure. Monitoring over the past six months has detected medium levels of ultraviolet radiation. But readings of more than 10 were recorded on 10 to 15 days each month last August and September.