Yajnas are ancient Vedic rituals in Hinduism that involve offerings made to deities through fire. These ceremonies are performed to seek blessings, prosperity, and harmony in the universe. The offerings typically include grains, ghee, and herbs, which are placed into a sacred fire while chanting specific mantras. The practice of yajna is believed to purify the environment and promote spiritual growth. It is often conducted during significant life events, festivals, or for communal well-being. The ritual emphasizes the importance of selflessness and the interconnectedness of all beings in the cosmos.