Nirjara is the exhaustion of karmic matter already acquired.
The karmas exhaust themselves by producing their results when it is time for them to do so.Unless they are exhausted before they are mature and start producing results, it becomes difficult to be free. By that time, new karmic matter begins to pour in.Therefore, it becomes necessary for one who desires final liberation to exhaust all karmas before maturity.
This is called nirjara. Nirjara is to be done by rigorous austerities.
Anasan – complete abstinence of eating and drinking
Alpahara – reduction in the quantity of food one normally eats
Ichhanirodha – control of desire for food and material things
Rasatyaga – complete abstinence of eating or drinking juicy and tasty foods such as honey, alcohol, butter, milk, tea, sweets, juice etc. (no attachments to the taste of the foods)
Kayaklesa – control of passions by discipline
Samlinata – sitting in a lonely place in due posture with senses withdrawn Internal
Prayaschita – repentance for the breach of vows
Vinaya – appropriate behavior towards a teacher
Vaiyavrata – selfless service to the suffering and deserving
Svadhyaya – studying/listening of religious scriptures
Bhutsarga – non-attachment to the body
Subha-dhyana – religious meditation