The obsession with Fairness and Skin Whitening is not only in India but majority of the South East Asian Countries…
To understand this better, it dates way back to the Vedic Times, where Apsaras (beautiful maidens, usually sent to lure men/distract men from their purposes) they are referred to as beautiful, supernatural female beings. They are youthful and elegant, and superb in the art of dancing and were described as fair skinned maidens. Whereas the evil women/Villains were described as being dark skinned.
In the ancient dynastic times, especially in hot climates, being fair meant being privileged, wealthy and noble and remaining indoors as the labor class had more melanin count due to labor outside. This was propagated during the British rule in India, where they subscribed to caste system that was prevalent in India, where upper caste typically had fairer skin and did not indulge in outdoor activities.
In Indian culture, colorism is taught to children in the form of fairy tales, just as the Grimms’ fairy tales featured light-skinned princesses or maidens; Indian mythological protagonists are typically fair and depict beauty, virtue, purity, and goodness.
Among children, it is rampant to see the fairer child being complimented more as being fair and lovely rather than for other accomplishments.