In the hierarchy of laws, the Constitution is supreme. All laws are subordinate to the Constitution. A law may be struck down as being unconstitutional due to lack of legislative competence or because it violates fundamental rights.
Decisions of the Union or State Executive, including decisions of statutory authorities, constitutional functionaries and quasijudicial authorities may be challenged in a State High Court under the Constitution. Rules, regulations, notifications and circulars passed by authorities under the relevant statute may also be challenged on the ground that the same violate the Constitution.