Excess melanin is produced in the skin by the effect of sunlight. It causes dark black spots on some parts of the skin which is known as melasma or melasma. The word melasma originates from the Greek word melas which means black. Mechta can be seen in all the areas of the skin where sunlight falls most, such as the upper cheeks , nose , lips and forehead. (Usually in the age group of 30-40 years). However, it is sometimes seen on the side of the neck , shoulders and upper arm. Those whose skin color is pale are more likely to be affected by mechta. There is a kind of mechta in the armpit. It is due to a hereditary disease. Whose name is neurofibromatosis. Ordinary mechta spoils the external beauty of man. However, it does not cause any damage inside the body. But there are some mechta that can be termed as skin cancer. Such as lentigo maligna , melanosa and basal cell carcinoma. However, if they are caught in the early stage, it is possible to cure them. There is no saying that everyone will be mechta when they go out in the sun. Hereditary tendencies are an important factor here. Studies have shown that the combination of genetic tendency and sunlight produces mechta. In some people, pigment cells or melanin increase at a significant rate with exposure to the sun's ultraviolet rays , not only because the outer layer of skin becomes thicker than before. Those whose skin color is black do not see mechta in that way. This is because sunlight or ultraviolet rays cannot affect black skin in that way.