By Swami Harshananda
India possesses more varieties of serpents than any single country in the world.
Serpent-worship, which is common even today, must have arisen from the fear entertained about the deadly effects of snakebites. Hence, the serpent-cult (nāgapujā and nāgabali) here may be considered as very ancient.
The dangers posed by snakes get intensified during the rainy season since their places of dwelling get drowned under water.
To ward off the dangers, the rite of offering a bali (oblation or a sacrifice) to serpents was performed on the Srāvaṇa-purṇimā day (full-moon day in the month of Srāvaṇa, generally in August) and continued everyday for four months till Mārgaśīrṣa-purṇimā (full-moon day in the month of Mārgaśīrṣa, generally in December).
Till this day, people were using (or advised to use) cots or some high furniture (inaccessible to snakes) which they were expected to discard now, get down
(= pratyavarohana) and sleep on the ground!
Thus pratyavarohaṇa became a religious rite.
- The Concise Encyclopedia of Hinduism, Swami Harshananda, Ram Krishna Math, Bangalore