Henna or Mendhi is a reddish dye with which the palms of women's hands are inked. This custom is deeply rooted in India, although it is also common in Pakistan, Yemen or Iran. These tattoos are a custom of the Vedic tradition and are considered as a way to bring out the inner Sun that every individual harbors. You have all the information in: «Indian customs«.
You have all the information in: "Indian customs".