When does the Court use the review powers?
The Court uses its review powers to examine the constitutionality of any law. When the Court concludes that a law is inconsistent with the provisions of the Constitution, it declares such a law as unconstitutional and inapplicable.
Specifically, the Court uses review powers in two main situations. First, when legislations violate fundamental rights of citizens. Second, in matters of federal relations, when a law is inconsistent with the distribution of powers laid down by the Constitution. For example, if the central government makes a law on a subject from the State list, the States can approach the Supreme Court, and if the Court agrees, it would declare the law unconstitutional.
Explanation
The textbook context clearly outlines when the Court uses review powers. The answer covers both grounds mentioned: violation of fundamental rights and violation of federal distribution of powers. The context also provides a concrete example of federal relations (Centre making law on State subject) which makes the answer more complete and exam-ready.