Yes, royalties arising due to copyright assignment is taxable in India. Royalties are nothing but compensation made to the owner of the copyright in view of using his/her work that may be assigned or licensed to such user. Royalties are usually paid periodically or otherwise on instances of the use of the copyright work.
As in any form of business, royalties paid, amounts to taxable income. As royalties are claimed as business income (in case of business owners) or if not self-employed, just income, they become subject to the laws under India’s Income-tax Act, 1961. (Royalty is defined under Section 9(1) (vi) of the Income tax Act, 1961).