Matsya Purana — Dynastic Genealogies: Paurava–Anu Lines
तेषां जनपदाः स्फीताः केकया भद्रकास्तथा सौवीराश्चैव पौराश्च नृगस्य केकयास्तथा //
teṣāṃ janapadāḥ sphītāḥ kekayā bhadrakāstathā sauvīrāścaiva paurāśca nṛgasya kekayāstathā //
Among their territories were flourishing realms—Kekaya and Bhadraka, as well as Sauvīra and Paurava; and likewise (there were) the Kekayas connected with King Nṛga.
This verse does not discuss Pralaya; it is part of a geographic-genealogical listing, naming prosperous janapadas (kingdoms/peoples).
Indirectly, it frames the political landscape of famed lineages and realms; such catalogues in the Matsya Purana support the ideal of orderly kingship by situating rulers (like Nṛga) within recognized peoples and territories.
No explicit Vastu/ritual rule appears here; the focus is on identifying regions and peoples, useful mainly for contextualizing later pilgrimage, donation, or royal-duty passages tied to specific lands.