I have heard that in Mahabharata after the kuruskhethra war. Yudhishtira became the emperor and later he handed over his kingdom to parikshith and so on. So my question is how did Hastinapuri empire collapse?
How did Kuru Dynasty or the empire of Hastinapura collapsed ?
The brief answer is provided by Shreemad Bhagwat Purana. Its mentioned in Skandha 9 - Chapter -22 , where Shree Shuka Deva is describing about the future kings of Panchal -Kaurava and Magadha kingdoms to the Parikshita. He here simply telling him the future to come. And who will be the last king. Shuka Deva is mentioning the Kuru Dynasty history from the beginning to Parikshita and telling him that there are four sons of him (Janamejaya, Srutasena, Bhimasena and Ugrasena ) , from which Janamejaya will start Sarpa-Yajna. The son of Janamejaya will be Satanika and his will be Sahasranika , and from him will come the son named Asvamedhaja. From Asvamedhaja will come Asimakrsna, and his son will be Nemicakra.
When the town of Hastinapura is inundated by the river, Nemicakra will live in the place known as Kausambi. There will be some more kings after Nemicakra and this dynasty will end with Kshemaka in Kali-Yuga.
Its also said that the Kshemak was overthrown by Sahadeva of Magadha dynasty.
गजाह्वये हृते नद्या कौशाम्ब्यां साधु वत्स्यति ।
उक्तस्ततश्चित्ररथस्तस्माच्छुचिरथः सुतः ॥SB 9.22.40॥
gajāhvaye hṛte nadyā kauśāmbyāḿ sādhu vatsyati | uktas tataś citrarathas tasmāc chucirathaḥ sutaḥ ||
When the town of Hastinapura [New Delhi] is inundated by the river, Nemicakra will live in the place known as Kausambi. His son will be celebrated as Citraratha, and the son of Citraratha will be Suciratha.
क्षेमकं प्राप्य राजानं संस्थां प्राप्स्यति वै कलौ ।
अथ मागधराजानो भाविनो ये वदामि ते ॥SB 9.22.45॥
kṣemakaḿ prāpya rājānaḿ saḿsthāḿ prāpsyati vai kalau | atha māgadha-rājāno bhāvino ye vadāmi te ||
In this Kali-yuga, Kshemaka will be the last monarch. Now I shall describe to you the future of the Magadha dynasty. Please listen.
And this is how the Hastinapura empire collapsed.
- First the Hastinapura city was destroyed by flooding from river Ganga.
- And then the last king of Kuru dynesty Kshemak was overthrown by another king in Kali-Yuga.