Short answers, pulled from the story.
The United States and France signed a trade treaty including a conditional most-favoured nation clause in 1778. This agreement marked one of the earliest formal uses of such language between sovereign states.
The World Trade Organization was created in 1995 after the emergence of the General Agreement on Tariffs and Trade post-World War II. WTO members must grant one another most favoured nation status unless exceptions are specified in their schedules.
India withdrew most favoured nation status granted to Pakistan in February 2019 following the Pulwama attack that killed over forty CRPF personnel during a terrorist assault. Article 21 allows any country to revoke MFN status without further explanation when national security is at stake.
The European Union considers MFN clauses potentially infringing Article 101 if they create appreciable adverse effects on competition. EU courts and regulators observe widespread use across industries including online travel agents where market power becomes significant.
Bangladesh, Maldives, Nepal, and Sri Lanka remain members of both SAARC and the WTO but have maintained their own MFN extensions to India. These nations were part of the group that received MFN status before the specific revocation toward Pakistan occurred.