Code of Civil Procedure, 1908–Order 1, Rule 10–Order of impleadment of private respondent–Sustainability–Suit for declaration and permanent injunction against UIT–No relief was sought against the private respondent (respondent no. 2)–It is not explained that how his rights would be prejudiced if he is not impleaded in the suit–Plaintiff is the dominus litis of suit and he cannot be compelled to implead a person as a party–Impugned order is liable to be quashed and set aside.