Mr SG - Read those posts, you said to have some major stocks on screen to look.
Also, googled for nifty index mgmt and found this :
http://www.nse-india.com/content/indices/nifty_freefloat_method.pdf
There is an index mgmt commitee too it seems :
Index maintenance plays a crucial role in ensuring the stability of the index, as well as in meeting its objective of being a consistent benchmark of the Indian equity markets.
IISL has constituted an Index Policy Committee, which is involved in the policy and guidelines for managing the S&P CNX Nifty. The Index Maintenance Subcommittee makes all decisions on additions and deletions of companies in the index.
Best,
B.G Maxine