Burning agarbatti (incense), dhoop and conducting vedic havans (sacrificial fire rituals) has been practiced in Bharat since thousands of years. These practices are known to create an ideal environment for worship, cleanse subtler energies, attract positive energies and repel negative one's. In fact, not just in Bharat but throughout the world in ancient cultures herbal smoke has been an important part of worship as well as medicine. However, it is in the current century that modern research has been able to understand the scientific basis of such practices. Without going into its metaphysical & spiritual aspects, here we will discuss the physical benefits of lighting incense, dhoop and conducting havans. 

So what does modern research say about dhoop and vedic havans?

1) Sanitizing the environment, naturally - A study published in the Journal of Ethnopharmocology in 2006 that reviewed ethnic remedies administered as smoke in 50 countries across 5 continents noted that, "The advantages of smoke-based remedies are rapid delivery to the brain, more efficient absorption by the body and lower costs of production". Greenmedinfo notes that thanks to another remarkable study published a year later in the same Journal, we now know that lighting dhoop or havans may be "one of the most powerful anti-septic technologies ever discovered". According to this study, 1 hour treatment of medicinal smoke generated by burning havan samagri (a mixture of wood and herbal medicines used in sacrificial fire rituals) reduced aerial bacterial population by over 94% in an open room environment, and the sanitized environment was maintained for the next 24 hours. In fact, certain species of pathogenic bacteria were completely eliminated and not detectable in the open room even after 30 days.