Justice K.S. Puttaswamy v. Union of India
Declared the Right to Privacy a fundamental right under Article 21 - the foundation of India's data protection law.
The background
Challenges to the Aadhaar programme raised a foundational question: is privacy a fundamental right? Older judgments had suggested it was not, so a nine-judge bench was constituted to settle the issue once and for all.
The decision
The Court unanimously held that the Right to Privacy is a fundamental right, intrinsic to the right to life and personal liberty under Article 21 and to the freedoms guaranteed in Part III of the Constitution. It expressly overruled the earlier decisions that had denied privacy this status.
What it changed
Puttaswamy is one of the most consequential modern judgments. It became the foundation for India's Digital Personal Data Protection Act, 2023, shaped limits on state surveillance and the use of Aadhaar, and underpinned later rulings on individual autonomy and dignity.