Does the EC have legal authority to disapprove Varun Gandhi's candidature?

WWhat are the powers of the EC after the Notification of Election? What are its powers in the matter of nomination, scrutunization  of nomination, withdrawal of candidate, pooling , declaration of result etc? Can EC debarred any candidate after the Notification of Election but before declration of election result?

After Notification of Election by the EC, what are the powers and functions of EC in the matter of Nomination of Candidate, scrutuization of Candidate,withdrawal of candidate, pooling and declaration of election result etc? Does EC possess power to debarred a Candidate from Contesting in between those period? If so, why do we have returning Officer etc? What is the true meaning of Election under the RPA?

Once a Notification is issued and the process of electing a candidate begins with nomination and withdrawal etc, can ECI intervene even before the result of election and ordered that a  particular Candidate can not stand as a Candidate? I failed to asy any reasons of the ECI.