When did these changes come into effect?
The changes mentioned in the context came into effect on various dates as follows:

1. Clause (5) was inserted by the Constitution (Forty-second Amendment) Act, 1976, s. 40 (w.e.f. 1-2-1977) and was omitted by the Constitution (Forty-fourth Amendment) Act, 1978, s. 31 (w.e.f. 20-6-1979).
2. Subsection (2) was substituted by the Constitution (Forty-second Amendment) Act, 1976, s. 41 (w.e.f. 1-2-1977).
3. The words "subject to the provisions of article 131A" were omitted by the Constitution (Forty-third Amendment) Act, 1977, s. 9 (w.e.f. 13-4-1978).
4. Clause (4) was inserted by the Constitution (Forty-second Amendment) Act, 1976, s. 42 (w.e.f. 1-2-1977).