Many Indian swimmers are obsessed with preserving their skin tone as light as possible just like many Europeans are obsessed with getting as heavy suntans as possible.
Anyway, here are a few tips for those who don't want to get any significant tan.
Remember, any sun tan will go away. The tan or pigmentation process occurs in the epidermis, the top skin layer. The epidermis replaces all its skin cells every 28-30 days. Cells in the inner portion of the top skin layer divide themselves, migrate to the surface, and flake off. Skin cells contain melanin, and as a result of UV exposure rises to the surface and flake off as well. Therefore, a tan can be maintained only by repeated exposure to UV light.
The light-skinned British colonialists were keen to pursue their favourite policy of "divide and rule" when they commissioned indologists like Max Muller to come up with the "Aryan invasion theory" that was so brilliantly debunked by Sri Aurobindo who explained that the reference to Aryans as "light" or "fair" had nothing to do with the skin colour but rather with the light of their aura. Sri Aurobindo proved that words like Dasa are used in the Rig Veda symbolically and should be interpreted spiritually, and that Dasa does not refer to human beings, but rather to demons who hinder the spiritual attainment of the mystic. Sri Aurobindo commented that in the RV III.34 hymn, where the word Arya varna occurs, Indra is described as the increaser of the thoughts of his followers: "the shining hue of these thoughts, sukram varnam asam, is evidently the same as that sukra or sveta Aryan hue which is mentioned in verse 9. Indra carries forward or increases the "colour" of these thoughts beyond the opposition of the Panis, pra varnam atiracchukram; in doing so he slays the Dasyus and protects or fosters and increases the Aryan "colour", hatvi dasyun pra aryam varnam avat." According to Sri Aurobindo (The Secret of the Veda), RV 5.14.4 is a key for understanding the character of the Dasyus: Agni born shone out slaying the Dasyus, the darkness by the light, he found the Cows, the Waters, Swar. Sri Aurobindo explains that in this verse the struggle between light and darkness, truth and falsehood, divine and undivine is described. It is through the shining light created by Agni, god of fire, that the Dasyus, who are identified with the darkness, are slain. The Dasyus are also described in the Rig Veda as intercepting and withholding the Cows, the Waters and Swar ("heavenly world"; RV 5.34.9; 8.68.9).
Ironically, the Hindus do not read the Hindu scripts, leave alone understand them. And those who visit the Sri Aurobindo Ashram or paste the Mother's symbol on their cars never care even to read what Sri Aurobindo, the Mother or other gurus say about the skin colour.