According to the Supreme Court's advisory opinion in In re Berubari Union (1960), what is needed to cede part of India's territory to a foreign State?

In In re Berubari Union and Exchange of Enclaves (1960), the Supreme Court advised that Article 3 covers changes to the areas and boundaries of States within India, not cession of Indian territory to a foreign State, which needs an amendment of the Constitution under Article 368. Parliament therefore passed the Constitution (Ninth Amendment) Act, 1960. Because cession alters the territory described in Article 1 and the First Schedule, neither executive action nor an ordinary law of Parliament, including one made to implement a treaty under Article 253, is enough.