Under what circumstances can amendments be proposed during a joint sitting?
Amendments can be proposed during a joint sitting under two circumstances:

(a) If the Bill, having been passed by one House, has not been passed by the other House with amendments and returned to the House in which it originated, no amendment shall be proposed to the Bill other than such amendments (if any) as are made necessary by the delay in the passage of the Bill.
(b) If the Bill has been so passed and returned, only such amendments as aforesaid shall be proposed to the Bill and such other amendments as are relevant to the matters with respect to which the Houses have not agreed.