It is an assamese tradition wear called Mekhela Sador.Which comes in two separate pieces-
Mekhela- The bottom portion draped from the waist downwards is called Mekhela.
Chador - The top portion of the two piece dress called Chador is a long length of cloth that has one end tucked into the upper portion of the Mekhela and the rest draped over and around the rest of the body.