On the basis of Astrology, Puranas, Scientific and Spiritual scriptures, it is mentioned that at the time of devasur war Amrit came out of Kumbha Samudra-Manthan. Indra Putra Jayant took that Amrit kalash, and established it at 12 places in which 8 are located in Devaloka and 4 are located in the Mritulok, while running to protect it from asuras

देवानां द्वादशाहोभिः मृत्येद्वादश बत्परेः । जायनत कुम्भपवांणि तथा द्वादश संख्यया॥।1 ।
पापापनुत्तये नृणां चत्वारि भुवि भारते। अष्टी लोकान्तरे प्रोक्ता देवैर्गप्या न चेतरै ।।2।।

Since Jayant took the Amrit Kalash, he has to revolved around the earth for 12 days and according to the calculation of Devaloka and Purans. One Day of Gods is equivalent to 1 years of mankind. Hence, this period becomes 12 years for mankind

पृथिव्यां कुम्भपर्वस्य चतुर्धा भेद उच्यते। चतुस्थले च पतनात् सुधा कुम्भस्य भूतले ॥
गंगाद्वारे प्रयागेच धारा गोदावरी तटे। कलशा््यो हियोगोऽयं प्रोच्यते शंकरादिभिः ॥

According to the legend, when Jayant took Amrit Kumbh to protect it, then these planet deities also played a major role in protecting Amrit Kalash.
Surya saved Kumbha from erupting, Moon prevented Amrit falling from Kumbha, Guru protected Kumbha's nectar from Asuras and Shani Dev kept an eye on Jayant so that he not to drink Amrit on his own (as per Skanda Purana)

As per Varaha Purana, At the time of the salvation of the earth, Shri Garuda has taken the Amrit Kalash from Devlok and rested on the Kadambh tree in Shri Dham Vrindavan and Also
After the struggle at Devlok, a plan was made by Devtas so as to set the future course while resting in Shridham Vrindavan

Because of This Bedhak name was given “Meeting place”.
Establishment places of Amrit Kalasha on Mritulok

1. Brahmakund, Haridwar
2. Triveni, Prayagraj (Allahabad)
3. Shipra Nadi, Ujjain
4. Bank of Godavri River, Nasik