Why is the color of Krishna’s skin blue ?
why not brown ? or white or black ?
Krishna was an actual historical figure, so his skin was surely not blue. It would have been some shade of brown. In fact, some scriptural references call his skin "dark as a thundercloud," suggesting that his skin may have been a darker shade of brown even than most of his contemporaries.
The blue skin is allegorical. In the Indian spiritual tradition, blue is considered the color of superconsciousness. (In fact, one of Paramhansa Yogananda’s chants starts like this: "Engrossed is the bee of my mind on the blue lotus feet of my Divine Mother.") Therefore it’s natural that Indian tradition would give its best-known human spiritual figures (Krishna and Rama) blue skin as a symbol of their great spiritual attainment, despite the fact that neither one would have had blue skin in his earthly incarnation.
The Indian mind is totally comfortable with such allegory; the Western mind often is not (at least, not until it realizes that it’s indeed an allegory).