The Delhi High Court thoroughly examined the principle of Constructive Res Judicata, which bars parties from raising issues in later proceedings that could have been raised earlier. It clarified that Constructive Res Judicata means any matter that should have been a ground of defense or attack in a previous suit is treated as if it was directly and substantially in issue in that suit. Although Section 141 of the CPC excludes Article 226 writ proceedings, the Court held that Constructive Res Judicata still applies to writs due to public policy, preventing multiple litigations and ensuring finality. Since the petitioner failed to challenge Clause 3.3 of the Guidelines in the earlier writ, the Court dismissed the current petition as barred by Constructive Res Judicata and not maintainable.