Delhi Chief Minister Arvind Kejriwal at a rock concert held at the Talkatora Stadium on Monday (Press Trust of India)

At a rock concert in Delhi on Monday, inserted between popular film songs and wild cheering were a string of announcements by Arvind Kejriwal.In a speech, the Chief Minister announced an education loan scheme and free Wi-Fi, among other things - music to the ears of thousands of Delhi University students but not to political rivals.The Aam Aadmi Party (AAP) has used the concert to influence students ahead of the Delhi University Student Union (DUSU) polls on September 11, alleges the Congress.On the party's complaint, an election official is investigating whether Mr Kejriwal and AAP violated rules by appearing at a concert organized by the Chhatra Yuva Sangharsh Samiti, the party's student wing, which is contesting the university polls for the first time.The concert featured celebrities like singer Shilpa Rao and composer Vishal Dadlani."Those who have been espousing clean politics and simplicity have violated every norm - we have written to the Vice Chancellor to take action against such blatant use of money," said senior Congress leader Ajay Maken.The complaint to the election officer of the university polls alleges that Mr Kejriwal had violated rules that prevent contestants from associating with any political leader or party during the college polls."Yes we've heard...the legal cell is looking into whether there's been a violation of rules. They can be disqualified even after the results," said DS Rawat, Chief Election Officer.AAP's candidates have turned the DUSU polls into a triangular contest for the first time; it has always been a direct battle between the Congress-backed National Students Union of India and the BJP's Akhil Bharatiya Vidyarthi Parishad.Rival student activists say in the history of their polls, never has a student body been promoted so openly by a political leader.This was denied by the AAP-backed group. Anmol Panwar, its vice president, said: "We are aware of the rules and we haven't violated any. We have the support of at least 30,000 students - they are worried."