World

Ganges is such a river, which satisfies all the three worlds,

1. Devaloka, 
2. Miryulok and 
3. Patal Lok 

with its holy water.

1. Therefore, it is also called Satya Ganga. 
2. Ganga is known as Bhogavati in Patal Lok and in 
3. Baitralok as Vaitarani

According to the Puranas, Ganga is called Mandakini in heaven and Bhagirathi in Patala