When did these changes come into effect?
The changes came into effect on 5-12-1992, 21-2-2002, and 28-9-2003. These dates are mentioned in the context as follows:

1. "Ins. by the Constitition (Seventy-second Amendment) Act, 1992, s. 2 (w.e.f. 5-12-1992)" indicates that an insertion was made to Article 333 on December 5, 1992.

2. "Subs. by the Constitution (Eighty-fourth Amendment) Act, 2001, s. 7, for "2000" (w.e.f. 21-2-2002)" shows that a substitution was made on February 21, 2002.

3. "Ins. by the Constitution (Ninetieth Amendment) Act, 2003, s. 2 (w.e.f. 28-9-2003)" indicates that another insertion was made on September 28, 2003.