Matsya Purana — The Observance of Ananta-Tritiya
प्रतिपक्षं तृतीयासु पुमानापीतवाससी धारयेदथ रक्तानि नारी चेदथ संयता //
pratipakṣaṃ tṛtīyāsu pumānāpītavāsasī dhārayedatha raktāni nārī cedatha saṃyatā //
On the third day of each fortnight, a man should wear garments that are not yellow; and if a woman is in her monthly course (menstrual flow), then she should remain restrained and self-controlled, observing the prescribed discipline.
Nothing directly—this verse is a conduct-and-observance rule (vrata/śauca), not a cosmology or pralaya passage.
It reflects household and social-dharma discipline: observing tithi-based restraints (such as avoiding certain colors) and maintaining regulated conduct during menstruation, emphasizing self-control and ritual propriety.
Ritual significance: it prescribes observance markers—clothing-color restriction on the third day of a fortnight and restraint during menstruation—typical of vrata and śauca-oriented ritual regulation.