29. The Presiding Officer shall, subject to such instructions as the Commission may give in this behalf, regulate the number of electors to be admitted to the polling station at a time and exclude from the polling station all other persons except- (a) any person on duty in connection with the election; ¹[(b) the contesting candidates and their election agents and one polling agent of each contesting candidate for each booth; (bb) election observers; and] (c) such other persons as may be specifically permitted by the Returning Officer.