Matsya Purana — Pṛthu
नोपसर्गभयं किंचित् पृथौ राजनि शासति नित्यं प्रमुदिता लोका दुःखशोकविवर्जिताः //
nopasargabhayaṃ kiṃcit pṛthau rājani śāsati nityaṃ pramuditā lokā duḥkhaśokavivarjitāḥ //
When King Pṛthu ruled, there was no fear of any calamity at all; the people were ever cheerful, free from suffering and grief.
It does not describe Pralaya; instead, it emphasizes that under a dharmic ruler like Pṛthu, society is protected from “upasarga” (public calamities), implying cosmic and social order rather than dissolution.
It presents the benchmark of kingship in Rajadharma: good governance should remove fear of disasters, maintain stability, and ensure citizens live with cheerfulness and without distress—an outcome of just administration, protection, and dharmic leadership.
No direct Vāstu/ritual rule is stated; the takeaway is contextual—temples, towns, and rituals flourish when governance is stable and free from “upasarga,” which is the social foundation for Vāstu and public rites.