Matsya Purana — Division of Bhārata-varṣa
आयुष्प्रमाणं जीवन्ति ये तु वर्ष इलावृते मेरोस्तु दक्षिणे पार्श्वे निषधस्योत्तरेण वा //
āyuṣpramāṇaṃ jīvanti ye tu varṣa ilāvṛte merostu dakṣiṇe pārśve niṣadhasyottareṇa vā //
Those beings who dwell in the region of Ilāvṛta—on the southern flank of Mount Meru, or to the north of the Niṣadha range—live out their full, allotted span of life.
It does not describe Pralaya directly; it belongs to cosmography, stating that inhabitants of Ilāvṛta (near Meru and north of Niṣadha) live for their full, divinely allotted lifespan.
Indirectly, it supports the Purāṇic worldview that different regions have different conditions of life; a king’s dharma includes governing in harmony with the cosmic order (deśa–kāla–niyati), acknowledging that human limits vary by realm.
No direct Vāstu or ritual rule is stated; the verse functions as a geographic-lifespan note within the Matsya Purāṇa’s mapping of sacred space around Meru.