Previous Year Question

Ultraviolet Radiation (UV) from the Sun is one of the major environmental causes of Skin Cancer. It is a part of the Electromagnetic Spectrum with wavelengths shorter than visible light. Excessive exposure to ultraviolet radiation can damage the Deoxyribonucleic Acid (DNA) of skin cells. If the cellular DNA Repair Mechanism fails to repair this damage completely, Genetic Mutations may develop. Such mutations can disrupt the normal regulation of cell division and contribute to the development of cancer.

Ultraviolet radiation is divided into three categories based on wavelength—UV-A (315–400 nm), UV-B (280–315 nm), and UV-C (100–280 nm). UV-A can penetrate relatively deeper layers of the skin and cause indirect DNA damage through Oxidative Stress. UV-B primarily affects the outer layer of the skin (Epidermis) and is a major cause of Sunburn and direct DNA damage. UV-C has the highest energy, but solar UV-C is absorbed by the atmosphere and normally does not reach the Earth's surface.

The major types of skin cancer associated with ultraviolet radiation include Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), and Melanoma. BCC generally develops from basal cells of the skin and grows relatively slowly. SCC originates from squamous cells of the skin, whereas Melanoma develops from Melanocytes, the cells responsible for producing Melanin. Melanoma can be more aggressive and has the potential to spread to other parts of the body. Prolonged sun exposure, repeated Sunburns, and excessive exposure to UV radiation increase the risk of developing skin cancer.

The Ozone Layer, located in the Earth's Stratosphere, protects living organisms by absorbing most UV-B and almost all UV-C radiation from the Sun. Depletion of the Ozone Layer can increase the amount of harmful UV radiation reaching the Earth's surface. In addition to skin cancer, ultraviolet radiation can cause Premature Skin Aging, Cataracts, and adverse effects on the immune system. According to the World Health Organization (WHO), sun protection measures should be adopted when the UV Index reaches 3 or above, including seeking shade, wearing protective clothing, hats, sunglasses, and using appropriate sunscreen.