Classification

Austerities are categorized into two groups:

External (Bahyantar): External austerities are noticed by others because they have a greater component of physical than psychic manner.
Internal (Abhyantar): Internal austerities are not noticed by others because they have a greater component of psychic than physical manner.

Each of these two austerities are further divided in six types:

External (Bahyantar):
Fasting Completely (Anasan)
Partial Fasting (Unodari)
Limiting the number of items of food (Vruti Sankshep)
Limiting desired tasty food (Ras parityag)
Bodily Endurance (Kayakalesh)
Controlling of the Senses (Pratisanlinata)

Internal (Abhyantar):
Atonement (Prayaschit)
Politeness (Vinay)
Serving others (Vaiyavachch)
Giving away (Vyutsarg)
Spiritual study (Sajzaya)
Meditation (Dhyan)