Landmark judgment from a division bench of the Apex Court.

From Paras 14 and 15,

14. The power to issue prerogative writs under Article 226 of the Constitution is plenary in nature and is not limited by any other provision of the Constitution. This power can be exercised by the High Court not only for issuing writs in the nature of habeas corpus, mandamus, prohibition, quo warranto and certiorari for the enforcement of any of the Fundamental Rights contained in Part III of the Constitution but also for “any other purpose”.
15. Under Article 226 of the Constitution, the High Court, having regard to the facts of the case, has a discretion to entertain or not to entertain a writ petition. But the High Court has imposed upon itself certain restrictions one of which is that if an effective and efficacious remedy is available, the High Court would not normally exercise its jurisdiction. But the alternative remedy has been consistently held by this Court not to operate as a bar in at least three contingencies, namely, where the writ petition has been filed for the enforcement of any of the Fundamental Rights or where there has been a violation of the principle of natural justice or where the order or proceedings are wholly without jurisdiction or the vires of an Act is challenged. There is a plethora of case- law on this point but to cut down this circle of forensic whirlpool, we would rely on some old decisions of the evolutionary era of the constitutional law as they still hold the field.

Citations : [1998 SCC 8 1], [1999 AIR SC 22], [1998 AIR SC 3345], [1999 BOMCR SC 2 70], [1998 JT 7 243], [1998 SCALE 5 655], [1998 SUPREME 8 176], [1998 AIR SCW 3345]

Other Sources :

https://www.casemine.com/judgement/in/575fd361607dba63d7e6e044