What is the opinion of Supreme Court regarding immunity and compulsion under Article 20 (3) of the Indian Constitution?

In a catena of cases, the Supreme Court held that immunity under article 20(3) does not extend to compulsory production of material objects or compulsion to give specimen writing, specimen signature, finger impression or compulsory exhibition of the body or giving of blood specimens. In State of Bombay v. Kathi Kalu the Apex Court held that compulsion regarding the documents is prohibited only if the documents convey the personal knowledge of the accused relating to the charge.