The process of Yajna (Yagna / Fire ritual) does not mere happen on material plane but also mental plane. In a faithfully performed fire ritual, the performer and participants, burn his/her mental vikrutis/disorders progressively, by concentration on selected Devata through Agni Devata as medium.
Since our Manomay sharir(s) are connected with universal mind, we can connect with minds of anybody and everyone with intense sadhana, once own mind is purified. At that juncture of Sadhana, one can help World by reducing pollution (Vikruti) in others minds and inject thoughts. (To understand this better,watch movie inception again with this context). Healthy Universal mind(s) means dharmic actions by majority in society. Although it is very crude and simple analogy, compare it with cloud computing to understand.
Fire ritual is a potent and to me game-changer ritual to reduce world miseries in this age of Tamas.