Klesha is the Sanskrit word for mental afflictions, corruptions or poisons. These 5 afflictions are:
-Fear of death [abhinivesha]
Avidya is spiritual ignorance, misunderstanding and incorrect knowledge.It can be defined as the misconception of taking the non-eternal as eternal,the impure for the pure, evil as good, the non-self for the self and perceiving pain as happiness.
All these misconceptions arise due to how we perceive this world-through our senses.Avidya is the foremost of the 5 kleshas.It is the field from which the other afflictions arise.
Asmita is the erroneous identification of ourselves with our own ego.The belief of I-am-ness.It is the mistaken identification with the sense objects.
Raga is the attachment to the senses and their objects that bring pleasure.Liking/attraction leading to mindless actions trapping us in an endless cycle of search for feelings of happiness.
Dvesa are the aversions that keep us from achieving what we truly seek.Aversions stem from unpleasant memories and mental preferences.
Abhinivesha is the fear of death and the willingness to live.Its the ignorant clinging to life and the desire for continuity.It also can be understand as a fear of change.
We are all born with these afflictions and they are the root causes for all the pain,suffering and diseases in life.In order to free ourselves from these mental corruptions,we need to enter into a spiritual life and walk the path of yoga.
We may do intense physical asanas,practice pranayama or prolonged meditations but the power of the kleshas will diminish all our efforts over and over again and bring us back to the beginning.All our efforts on the spiritual path will be in vain if we do not work on the impurities in our personality.
The physical reality is called prakriti [nature].It is made up of the 3 gunas [qualities] sattvas,rajas,tamas [goodness,passion,dullness].They are in constant interaction and can create imbalances.Only the yogi will be able to get a grip on these fluctuations.
The yogi who has had the experience of merging his consciousness with the pure divine consciousness will become situated in his own essential nature,the self,the Purusha [spiritual consciousness].
This is the fundamental philosophical system of Samkhya Yoga.
The antidotes for a yogi to counteract the kleshas are tapas, kriyas, svadhyaaya and dhyana.The first stage is simply to acknowledge them for what they are.
After that, a yogi needs to practice austerities [tapas] of the physical body and mind in order to get hold over the senses and destroy the mental impurities.Svadhyaaya is the study of the self and the study of holy Hindu scriptures that will bring a shift towards the self, recognizing the self as divine consciousness.
Kriyas need to be practiced as tools to purify the body and mind.
The final and most powerful antidote to overcoming the kleshas is Ishvara Pranidhana, the most subtle level of devotional practice where the focus is placed on the worship of a higher power.This kind of dhyana [meditation] will eventually lead to the mastery of the senses and destroy the kleshas.