This fire ceremony dates back to the Vedic period when havans were very much part of daily life. Havans are still conducted quite frequently in yoga centers in India, especially during spiritual events.
During a havan, the fire altar is usually square shaped, almost always built specifically for the occasion and dismantled immediately after the ritual is completed. The ritual is always centered in the middle of the appointed space, whether conducted outdoors or indoors. Priests and other principal people performing the ceremony sit around the altar while the other devotees form a larger ring around the fire.
There are many different types of havans for different occasions. There is a havan for naming a child, a havan for wealth and material prosperity, and one that is a purification ritual performed as part of the formal ceremonies by which a person takes the vows of renunciation.
It is believed that havan has a purifying effect on both the devotee who makes the offerings and the environment. Through the chanting of mantras and making offerings to the fire, one’s chakras are re-energized, creating a revitalizing and rejuvenating effect for both the body and mind.
In one's personal spiritual practice, havans can be conducted as a prop for an internal process of meditation.