For The Married Woman Only
Marriage is a very crucial part of life in society, in India, especially for women. They even have a special set of body decoration patterns and even ornaments that only a married woman is allowed to have. Usage of the same by an unmarried woman is strictly forbidden in that society.
Many communities and cultures across the world also have their ways of distinguishing married women from the rest too, but the Indian way of doing it is unusual. It stands out. That a married and unmarried woman in India, unlike other parts of the world where that happens a lot.