1.1 Kumar et al., (2020). A study was aimed to present the available literature that advocates the efficacy of hawan i.e., traditional fumigation technique to change the biome via killing of pathogenic microorganisms i.e., bacteria, fungus, and viruses in the environment. The fumigation through Hawan was aimed to offer the medicinal herbs or ingredients to the fire of agnihotra. The fire of agnihotra was turning the medical herbs or samidhas into nanoparticles that act to alter the biome. The fumigation through Hawan was a common cultural ritual among ancient practices believed to promote health and well-being of the individuals. This review was put forward several suggestions for the importance of hawan as follows (i) The studies needed in near future to assess and validate the viral load, infectivity of the virus and helpful in reducing the chances of occurrence of diseases like flu and its complications and (ii) need of studies that estimates the viral content from the atmosphere with the use of advanced technologies
1.2 Nautiyal et al., (2007). The objective of the study was to find the effects of Medicinal smoke in reducing airborne bacteria. In this study observed that after 1 hour treatment of medicinal smoke on an aerial bacterial population, there is over 94% reduction of bacterial counts by 60 min and the ability of the smoke to purify or disinfect the air and to make the environment cleaner was maintained up to 24 hours in the closed room and absence of pathogenic bacteria in the open room even after 30 days. Thus, the present study showed encouraging results regarding the effectiveness of Medicinal smoke in reducing airborne bacteria
1.3 Harsha, et al., (2017) The objective of the study was to find the effects of Vastu Homa in the management of bacterial and fungal count. For this study, Vastu homa was conducted in three new buildings. The air sampler was kept at a specific distance from the homa kunda in different directions and samples were collected before, during and after the homa process and both bacterial and fungal counts were analyzed and compared. The results revealed significant reduction in microbial count in all three buildings. Thus, the present study showed encouraging results regarding the effectiveness of Vastu Homa in the management of bacterial and fungal count.
1.4 Deogade, (2020). The objective of the study was to find the effects of Agnihotra in the prevention and control of Covid-19. Epidemic or pandemic (Janapadodhwansa) occurs due to vitiation of Vayu (air), Jala (water), Desh (area), and Kala (season). The atmosphere got contaminated by such pathogens. Fumes of Homa and various medicinal plants used in this therapy sterilise the atmosphere or place where it is performed and hence it may help to eradicate the SARS-CoV-2 as it lives on surface and aerosols. Thus, various studies showed encouraging results regarding the effectiveness of Agnihotra in the prevention and control of various communicable diseases like Covid-19.