A division bench of Supreme Court held as follows,

As a general rule, suppression of a material fact by a litigant disqualifies such litigant from obtaining any relief. This rule has been evolved out of the need of the Courts to deter a litigant from abusing the process of Court by deceiving it. But the suppressed fact must be a material one in the sense that had it not been suppressed it would have had an effect on the merits of the case. It must be a matter which was material for the consideration of the Court, whatever view the Court may have taken.

The existence of an adequate or suitable alternative remedy available to a litigant is merely a factor which a Court entertaining an application under Article 226 will consider for exercising the discretion to issue a writ under Article 226 . But the existence of such remedy does not impinge upon the jurisdiction of the High Court to deal with the matter itself if it is in a position to do so on the basis of the affidavits filed. If however a party has already availed of the alternative remedy while invoking the jurisdiction under Article 226, it would not be appropriate for the Court to entertain the writ petition. The Rule is based on public policy but the motivating factor is the existence of a parallel jurisdiction in another Court. But this Court has also held in C. B. Gosain Bhan V. State of Orissa 14 STC 766= 1963 (2) SCR 879 that even when an alternative remedy has been availed of by a party but not pursued that the party could prosecute proceedings under Article 226 for the same relief. This Court has also held that that when a party has already moved the High Court under Article 226 and failed to obtain relief and then moved an application under Article 32 before this Court for the same relief, normally the Court will not entertain the application under Article 32. But where in the parallel jurisdiction, the order is not a speaking one or the matter has been disposed of on some other ground, this Court has, in a suitable case, entertained the application under Article 32 . Instead of dismissing the writ petition on the ground that the alternative remedy had been availed of the Court may call upon the party to elect whether it will proceed with the alternative remedy or with the application under Article 226. Therefore the fact that a suit had already been filed by the appellant was not such a fact the suppression of which could have affected the final disposal of the writ petition on merits.

Finally,

In this case, admittedly the appellant has withdrawn the suit two weeks after the suit had been filed. In other words the appellant elected to pursue its remedies only under Article 226. The pleadings were also complete before the High Court. No doubt, the interim order which was passed by the High Court was obtained when the suit was pending. But by the time the writ petition was heard the suit had already been withdrawn a year earlier. Although the appellant could not, on the High Court’s reasoning, take advantage of the interim order, it was not correct in rejecting the writ petition itself when the suit had admittedly been withdrawn, especially when the matter was ripe for hearing and all the facts necessary for determining the writ petition on merits were before the Court, and when the Court was not of the view that the writ petition was otherwise not maintainable.

Citations : [2004 SUPREME 5 485], [2004 JT SUPP 2 601], [2004 ALLMR SC 5 793], [2004 SCC 7 166], [2004 AIR SC 2421], [2004 SCR 3 56], [2004 SCALE 3 374], [2004 ALD SC 5 84], [2005 ALT 2 4], [2004 BLJR 3 1739], [2005 COMPLJ SC 4 503], [2004 JCR SC 2 284], [2004 PLJR 2 171], [2004 COMPCAS SC 121 99]

Other Sources :

https://indiankanoon.org/doc/1770523/

https://www.casemine.com/judgement/in/5609adffe4b0149711412a94