The Right to Privacy was declared a fundamental right by the Supreme Court in K.S. Puttaswamy v. Union of India (2017). The nine-judge bench overruled ADM Jabalpur and M.P. Sharma judgments, establishing privacy as intrinsic to Article 21. The judgment laid groundwork for data protection laws, influencing the Personal Data Protection Bill 2019 and subsequent Digital Personal Data Protection Act 2023. It established the three-fold test for privacy restrictions: legality, necessity, and proportionality.

The Puttaswamy judgment transformed India's constitutional landscape by recognizing privacy as a fundamental right under Article 21, overturning decades of precedent. Justice K.S. Puttaswamy challenged Aadhaar's constitutionality, leading to a comprehensive examination of privacy rights. The Court established that privacy encompasses informational self-determination, bodily autonomy, and personal liberty. The three-fold test requires any state interference with privacy to be backed by law, necessary for legitimate state interest, and proportionate to the objective sought. This framework directly influenced subsequent legislation including the Digital Personal Data Protection Act 2023, which operationalizes data protection principles. The judgment addressed concerns about surveillance, biometric data collection, and algorithmic profiling. It recognized that privacy rights aren't absolute and can be restricted for compelling state interests like national security, but only through constitutional procedures. The decision's impact extends beyond Aadhaar to encompass digital rights, healthcare data, financial information, and emerging technologies like AI and facial recognition systems.