In some countries the dark skin hierarchy go so far as to affect even social class and job opportunities. Many South Asian women grew up constantly being told to avoid sunlight for the fear of growing darker. Growing darker, of course, meant becoming less attractive.
It also may lead to surgery in order to 'correct' dark skin which stray from the European-based ideal of fair-skin.
In 1999 it was discovered that bleaching creams for dark skin, which are so popular among women in South Asia, can burn the skin because they remove the inherent melanin protection of dark skin. Most bleaching creams contain hydroquinone which blocks the production of melanin and also destroys the skin's melanocytes, thus increasing to dark tanning skin sensitivity.
Generally, people with dark skin have more melanin, the natural pigment that helps protect skin cells and DNA from damage. Different people have different amounts of melanin in their skin. Those with a Northern European background tend to have less melanin and be rather pale, whereas people with dark brown or black skin, like many people from Africa, have more. Recent research shows that complex factors, such as skin type, genes, and melanin distribution -- may be as important in determining skin cancer risk as race and skin color are. Dark skin provide protection against UV effects on the immune system reduce rates of skin cancer. The Phillipine Dermatological Society says that dark  skin has a natural SPF of 4-5.  Whatever your skin colour, sunscreen may be a good idea if you're planning extended intense sun exposure, such as a day at the beach. If you decide to use sunscreen, what SPF do you need? Most  cosmetologists recommend an SPF of 6-15 for dark skin. Clothing is a completely safe way to protect against sun damage: loose long clothing is ideal for protection, as are long pants and shirts. Cotton clothing has a UPF (equivalent to SPF) of about 5, well-washed cotton is even better. BUT! Remember that sunscreen is necessary only for the exposed parts of the dark skin  body. Otherwise your dark skin will get vitiligo- the result of the disappearance of the skin's melanocytes. but , people with dark skin may face much more problems concerning dark tanning, as fair -skinned ones. If europeans need to only to protect their skin, persons with dark skin must also not to overuse sunscreens in order their skin not to bleach. On the contrary, people with dark skin must take care of it with much more attention as those with other typesþ but the thing is that dark skin individuals are apt to think just the contrast thing - they are absolutely free from both skin cancer types and photoaging consequences.  
Researchers think pigment may be destroyed as the body responds to a substance it perceives as foreign. While pigment is forming, toxic by-products could be produced and destroy melanocytes. Typical skin bleaching shows areas of milky-white skin on the background of dark skin . But I do believe that it will never danger your dark skin, if you just take the les care  of protecting it- using the least of sun protection and never depriving yourself of the joy of sunbathing.

dark tanning