Mental pollutions are the cause of physical and environmental ravages. They are engendered by greed, lust and anger. Disharmony, conflict, sickness and degradation of nature are their results. The important thing about actions is the motive with which they are done. Psychological and social motivations and implications of activities are important.
All actions start in the mind.
Evil deeds are caused by ignorance and selfishness. If the ego is allowed to grow, it generates anger, greed, lust, hatred, etc. and makes life miserable for all. They should be offered in fire. Mental environment has to be kept clean and focused. Yajna is the sacrificing of one's ego and the burning of impurities.