In R. K. Narayan's short story "A Willing Slave" (which I read as part of his 1982 collection Malgudi Days), the nanny Ayah tells a story to the young girl Radha:
The Ayah squatted below the cot and narrated the story of the black monkey which rolled in a sack of chalk powder, became white and married a princess; at the wedding somebody sprinkled water on him and he came out in his true colour; he was chased out; presently a dhobi took pity on him and washed, bleached and ironed him, in which state he regained the affection of the princess.
Is this a real fairy tale told in some Indian culture? I searched the internet for Indian stories about a black monkey and a princess, but failed to find anything that fits. Perhaps someone with more subject knowledge will know the answer.