UV rays can cause sunburn, alteration of connective tissue of dermis, tanning of skin and even skin cancer and other diseases.
Ordinarily, we can get only limited protection against UV rays even by sitting in shade as under a tree.
Curiously, however, the UV rays cannot penetrate glass. Thus we can protect our eyes against UV rays by wearing sun-glass of various kinds. If eyes are not protected against UV rays, we can contract even cataract. If we consult a doctor or a scientific expert, he may tell us about several hazards which may be caused by UV radiations.
We can take certain steps to protect ourselves against the fury of UV radiations, such as keeping infants in shade, limiting midday sun, wearing hat, sunglasses, protective clothing, applying sunscreen, etc.
It is rightly said that we should not look at the sun at the time of solar eclipse as that way; we can get our eyes harmed by the UV rays emitted by the sun.