With the onset of the tretayuga, greed gave rise to malice in its wake, malice led to falsehood, and falsehood led to passion, anger, vanity, hatred, cruelty, aggression, fear, grief, anxiety, distress and the like. Symbolically, during tretayuga, one-fourth of dharma (religious duties) disappeared, resulting in reduction of the life-span of human beings by a quarter. Similarly, there was reduction in the attributes of earth etc., by a quarter. Because of the reduction of these attributes there was diminution by one quarter of the unctuousness, purity, tastes (rasa), potency (veerya), post digestive effects (vipaka), prabhava and qualities of grains. In effect, this degradation impacted all aspects of living beings that were described to have existed in the satyayuga. There was an unusual change in the maintenance of equilibrium of tissue elements and there was vitiation of agni (pitta) and maruta (vata) by which, first of all, bodies of living beings got afflicted with diseases viz. jwara (fever) etc. Therefore the life-span of living beings underwent gradual diminution.
english translation