An affidavit is a sworn statement made by a party, in writing, made in the presence of an oath commissioner or a notary public which is used either in support of applications to the Court or as evidence in court proceedings. In case of Writ Petitions, cases are generally disposed of on the basis of affidavits.
Counter affidavit is an affidavit filed by the respondent in reply to a petition. Respondent files reply to the petition in the form of affidavit. In most of the Writ Petitions, reply is being filed in the form of Counter Affidavit.
Rejoinder Affidavit is the response by the petitioner to the counter affidavit filed by the respondent. Rejoinder affidavit may include response to the response to the new facts raised through the affidavit filed by the respondent. Rejoinder is reply to the Counter Filed by the Opposite party . The Pleadings of Petitioner or plaintiff are already filed and the opposite party filed counter affidavit or Written Statement with new fats which are not correct according to Petitioner or Plaintiff, in reply to the Counter of Respondent the petitioner can file rejoinder denying the new facts which are not mentioned in the Petition or Complaint.
For the new facts the complainant will file additional statement, with support of an affidavit. First show the reason to the court that why the petitioner is filing additional statement and then take the order from the court for filling it.