The fall in index is due to the fact that most FIIs are selling stocks in bulk to book profits and again buy with least 20% discounted rates.
this is merely speculation and nothing to do with parameters such as PE, EPS,etc. they just want to make money from this casino.
steps that could be taken
firstly there must be a certain lock in period for Mutual funds groups and institutional investors.
secondly for all forgiven investors there must be a certain Tobin tax if they move there investments from one country to other.