Fundamental Rights
(1) The right to move the Supreme Court by appropriate proceedings for the enforcement of the rights conferred by this Part is guaranteed. (2) The Supreme Court shall have power to issue directions or orders or writs, including writs in the nature of habeas corpus, mandamus, prohibition, quo warranto and certiorari, whichever may be appropriate, for the enforcement of any of the rights conferred by this Part. (3) Parliament may by law empower any other court to exercise, within local limits, all or any of the powers of the Supreme Court under clause (2). (4) The right guaranteed by this article shall not be suspended except as otherwise provided by this Constitution.
This is often called the "heart and soul" of the Constitution by Dr. B.R. Ambedkar: it guarantees you the right to go directly to the Supreme Court if any of your Fundamental Rights are violated, and empowers the Court to issue special orders ("writs") to fix the violation - including ordering the release of someone illegally detained (habeas corpus) or commanding a public authority to do its duty (mandamus). High Courts have a similar, even broader writ power under Article 226.
If a Fundamental Right is violated and ordinary remedies are too slow or unavailable, a person (or, for public-interest matters, sometimes even someone acting on their behalf) can file a writ petition directly in the Supreme Court under Article 32, rather than starting from a lower court.