Srimad Bhagavatam Canto 05, Chapter 20, Text 27

SB 5.20.27

tad-varsa-purusa rtavrata-satyavrata-danavratanuvrata-namano bhagavantam vayv-atmakam pranayama-
vidhuta-rajas-tamasah parama-samadhina yajante.
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The inhabitants of those islands are also divided into four castes — Rtavrata, Satyavrata, Danavrata and Anuvrata — which exactly resemble brahmana, ksatriya, vaisya and sudra. They practice pranayama and mystic yoga, and in trance they worship the Supreme Lord in the form of Vayu.
Srimad Bhagavatam Canto 05, Chapter 20, Text 26
Srimad Bhagavatam Canto 05, Chapter 20, Text 28