India's Constitution adopted 'procedure established by law' under Article 21, rejecting the American 'due process of law' standard at the Constituent Assembly stage. Yet through landmark rulings — Maneka Gandhi (1978), Francis Coralie (1981), and the Right to Privacy judgment (2017) — the Supreme Court progressively read substantive fairness into Article 21, effectively importing due process values without amending the text. Today, any law curtailing life or liberty must be just, fair, and reasonable.

The distinction between 'procedure established by law' and 'due process of law' is one of the most consequential doctrinal choices in Indian constitutional history.

The American Fifth and Fourteenth Amendments guarantee that no person shall be deprived of life, liberty, or property without 'due process of law.' This standard has two components: procedural due process (notice, hearing, impartial tribunal) and substantive due process (the law itself must be reasonable, not arbitrary).

India's framers deliberately chose the narrower formula. Article 21 reads: 'No person shall be deprived of his life or personal liberty except according to procedure established by law.' Dr. B.R. Ambedkar and the Constituent Assembly rejected Sir Alladi Krishnaswami Ayyar's proposal to insert 'due process' fearing that judges might invalidate social welfare legislation as unreasonable — a concern drawn from early 20th-century American experience (Lochner era).

A.K. Gopalan v. State of Madras (1950) confirmed this narrow reading: the Supreme Court held that each Fundamental Right operates in a separate watertight compartment, and if the procedure prescribed by a valid law was followed, Article 21 was satisfied.

Maneka Gandhi v. Union of India (1978) demolished this reading. A seven-judge bench held that the word 'law' in Article 21 cannot be any law — it must be right, just, and fair. Procedural requirements must satisfy Articles 14 (non-arbitrariness) and 19 (reasonableness), creating a 'golden triangle.' This effectively introduced substantive due process through judicial interpretation.

Francis Coralie Mullin v. Administrator (1981) extended the right to life beyond mere animal existence to include the right to live with dignity.

The nine-judge bench in K.S. Puttaswamy v. Union of India (2017) unanimously held that the right to privacy is a fundamental right under Article 21, and expressly used substantive due process reasoning to test restrictions on it.

In practice, the current Indian position mirrors substantive due process: a law depriving life or liberty must (1) be a validly enacted law, (2) be just, fair, and reasonable (not arbitrary under Art. 14), and (3) not unreasonably restrict freedoms under Art. 19.