Sri Swami Sivananda explains correlation between Lokas and Chakras in his book Kundalini Yoga and in this page. He says Lokas correspond to Chakras of human body.
Man is a microcosm (Kshudra Brahmanda). Whatever exists in the outer
universe exists in him. All the Tattvas and worlds are within him and
so is the Supreme Siva-Sakti. The body may be divided into two main
parts, namely, the head and trunk on the one hand, and the legs on the
other. In man, the centre of the body is between these two, at the
base of the spine where the legs begin.
The Surya Mandal or the fire is in the Nabhi or the navel. The Chandra
Mandal or the sphere of Amrita is a little below Ajna Chakra.
Supporting the trunk and
throughout the whole body there is the spinal cord. This is the axis
of the body, just as Mount Meru is the axis of the earth. Hence, man’s
spine is called Merudanda, the Meru or axis-staff. The legs and feet
are gross which show less signs of consciousness than the trunk with
its spinal white and grey matter; which trunk itself is greatly
subordinate in this respect to the head containing the organ of mind,
or physical brain, with its white and grey matter. The positions of
the white and grey matter in the head and spinal column respectively
are reversed.
The body and legs below the centre are the seven lower
or nether worlds upheld by the sustaining Sakti or Powers of the
universe. From the centre upwards, consciousness more freely manifests
through the spinal and cerebral centres. Here there are the seven
upper regions or Lokas, a term which means “What are seen” (Lokyante),
that is, experienced, and are hence the fruits of Karma in the form of
particular rebirth.
These regions, namely, Bhuh, Bhuvah, Svah, Tapa,
Jana, Maha and Satya Lokas correspond with the six centres; five in
the trunk, the sixth in the lower cerebral centre; and the seventh in
the upper brain or Satyaloka, the abode of the Supreme Siva-Sakti.
The Chapter Human Body - A Miniature Cosmos : Departure of Soul to the next Lokas of Skanda Purana describes this correlation in detail.
