Now let us have look at the nether worlds described in Hinduism.
They are Seven.
Above the planetary systems where humans live is the sky.
Above the sky is the orbiting sun, the entrance point of the heavenly planetary systems.
This is the middle of the universe where begins the planets of those elevated by great austerities and penances.
The planets above these, up to Satya-loka are the residences of those advanced in spiritual knowledge.
These lower planetary systems are the same size as the earth planet, begin 560,000 miles below earth.
Sunshine does not reach these planets and light comes from jewels on the hoods of serpents.
These planets are populated by persons of great power and opulence with no Dharma.
They have become thus because of severe penance ,Tamasic.
They do not Age nor are they afflicted by Disease..
These places are called he “bila-svarga”, or subterranean heavenly planets.
The residents here enjoy a better Lifestyle than the Devas.
All residents drink juices and bathe in herbal elixirs which free them from anxiety disease, and signs of physical aging.
Anxiety and fear consume them at the time of dissolution.
Beneath the planet Patalaloka, and slightly above the water of the Garbhodaka ocean, are the Naralokas, or the hellish planetary systems.
There is another interpretation that these Lokas are the Americas.
Read my post ‘America Patala Loka ‘
There are 28 different hellish planets described in the Vedic literature.
Please read my Post on this.
Vishnu Puran,Garuda Puran.