A relinquishment deed is a legal instrument which an heir can leverage to transfer or release his legal right of an inherited property to another person.
Must be registered: Under Section 17 of the 1908 Registration Act, it is mandatory that a relinquishment deed must be registered for it to be valid.
In Delhi, For a Relinquishment deed, stamp duty is 6% in the case of men and 4% in the case of women. The stamp duty should be paid through Collector of Stamps/SDM. Registration fee of a Relinquishment Deed is 1% of the total value of Deed along with Rs. 100/- pasting charges.
A relinquishment deed can be done with or without any consideration.
The web link you have referred here is about the judgments, the test to determine whether an instrument can be considered as a Release/Relinquishment Deed.
The following points were discussed in the judgment and not about the stamp duty what you refer here or the main query is about:
a. In determining whether the document is a release or Gift/Conveyance, the nomenclature used to describe the document or the language which the party may choose to employ in framing the document, is not a decisive factor. What is decisive is the actual character of the transaction intended by the executants;
b. Determination of the nature of the document is not a pure question of law;
c. Where a co-owner renounced his right in a property in favour of the other co-owner, mere use of word like 'consideration' and 'transfer' would not affect the true character of the transaction;
d. What is intended by a Release Deed is the relinquishment of the right of the co-owner;
e. Co-ownership need not be only through inheritance, but can also be through purchase;
f. Where the relinquishment of the right by the co-owner is only in favour of one of the co-owner and not against all, the document would be one of Gift/Conveyance and not of "release".