Q: What are residuary powers in Indian Constitution ?

Ans: Residuary powers of legislation is mention in Article 248 in the Constitution of India, in which Parliament has exclusive power to make any law respect to any matter not enumerated in the Concurrent List or State List.

Such power shall not include the power of making any law imposing a tax not mentioned in either of those lists.

But in case of national interest,  it can also make laws on state list if passed by 2/3 of resolution.