Matsya Purana — Bhīma-Dvādaśī
वैवस्वताख्ये संजाते सप्तमे सप्तलोककृत् द्वापराख्यं युगं तद्वद् अष्टाविंशतिमं जगुः //
vaivasvatākhye saṃjāte saptame saptalokakṛt dvāparākhyaṃ yugaṃ tadvad aṣṭāviṃśatimaṃ jaguḥ //
When the seventh Manvantara, known as Vaivasvata, had arisen, the Maker of the seven worlds likewise declared that the Dvāpara Yuga there is the twenty-eighth in the count.
It does not describe Pralaya directly; it focuses on cosmic timekeeping—how yugas are counted within the Vaivasvata (seventh) Manvantara.
Indirectly, it situates dharma within a yuga framework: the Matsya Purana often explains that duties and social order are interpreted according to the yuga and manvantara context.
No Vāstu or ritual procedure is specified in this verse; its significance is chronological—useful for aligning rituals, genealogies, and Purāṇic narratives to yuga-manvantara counts.