The 101st Constitutional Amendment Act, 2016 created the legal framework for Goods and Services Tax by inserting Articles 246A, 269A, and 279A. It subsumed multiple central and state indirect taxes into a unified GST regime, which came into effect on 1st July 2017. The GST Council under Article 279A was constituted as a federal body with representation from Union and all States.

1. 1 Pick up Constitution of India.
2. 2 Go to Article 246A (Special provision for GST).
3. 3 Look for marginal note: '[Ins. by Constitution (101st Amdt.) Act, 2016]'.
4. 4 If found → answer is 101. If your edition doesn't have marginal notes → you need pre-exam memorization.

The text reads: The 101st Amendment inserted Article 246A empowering both Parliament and State Legislatures to make laws on GST, and Article 279A establishing the GST Council as a constitutional body for inter-governmental coordination on indirect taxation.