This is called “bandhni” or “chundri”. It’s a type of tye dye technique that is also popular in Gujarat, India, and the Kutchi community. It can be done on pure silk or cotton.
In Pakistan, it’s a very popular choice for mehndi & mayoun dresses.
My gujju friends in college once told me that in India, certain colors are used to signify things like red bandhani is for brides obviously etc.