Step 1: Understand the question.
The Bharatiya Sakshya Adhiniyam, 2023 is the new evidence law that replaces the Indian Evidence Act, 1872. We must find the body where this strict evidence law does NOT apply.
Step 2: Know what evidence law does.
Evidence law tells us what facts can be proved, how they are proved, which documents are allowed, and who carries the burden of proof. Courts and many tribunals follow these rules.
Step 3: See why arbitration is different.
Arbitration is built on the choice of the parties. It values party freedom, consent, flexible steps, and speedy results. To keep these benefits, the Arbitration and Conciliation Act says arbitral tribunals are NOT bound by the strict rules of evidence.
Step 4: See what this flexibility means.
An arbitrator can still act fairly, but may accept documents that do not strictly meet evidence rules and may follow simple steps agreed by the parties. This makes arbitration faster than court cases.
Step 5: Check the other options.
The National Company Law Tribunal, the Income Tax Appellate Tribunal, and the National Green Tribunal are statutory bodies that generally apply evidence principles while deciding. So the strict evidence law is not switched off for them in the same way.
Step 6: Reach the answer.
The clear exception is arbitration, which is meant to run with flexibility and party choice. So the Adhiniyam does not strictly apply to an arbitral tribunal.
\[ \boxed{\text{Arbitral Tribunal}} \]