Paithani sarees are traditionally associated with the town of Paithan in Maharashtra, the Katan Silk Maharani Paithani is a unique variation that is not specifically tied to any single city. It is a type of Paithani saree that is woven using Katan silk. Mumbai city has a large selection of saree shops, and you should be able to find Katan Silk Maharani Paithanis here as well. https://www.ompaithani.com/product/pure-silk-handloom-maharani-paithani-saree/