'Mahi ink' which is in news, is from which state?

Mahi ink was developed in Assam. The technique involves extracting ‘mahi’ using cow urine from a cocktail of fruit pulp and tree bark such as haritaki, amla, bibhitakhi or bhomora, mango and jamun — often infused with the blood of eels or catfish. Recently, researchers are planning to recreate the lost techniques of manuscript writing using the ink.