To use all the elements of the poem which beautifies the poem in appropriate place is called Auchitya.
Comes from Hindi word ‘Uchit’, which means appropriate. To use Rasa, Alankar, Riti etc in appropriate place in poetry is called Auchitya.
According to Kshemendra, whatever is improper, detracts from Rasa, hence is to be abandoned (an-uchit)
The theory of propriety or appropriateness claims that in all aspects of literary composition, there is the possibility of a perfect, the most appropriate choice - of a subject, of ideas, of words, of devices. The concept of propriety with reference to custom, subject, character and sentiment recurs in almost all theorists and is often discussed in association with figures of speech, guna/dosa and ritis. It has been used for propriety in delineating bhavas according to characters, and in the choice of margas (for example, in the use of compounds, etc.) according to the speaker, content and type of literary composition. Ksemendra made Aucitya the central element of literariness. He defines Aucitya as the property of an expression (signifier) being an exact and appropriate analogue of the expressed (signified).
In verses 8-10 of his book, Ksemedra enumerates the areas, locations or sites of literary compositions where the concept of aucitya is pertinent: Pada (phrase), vakya (sentence), prabandhartha (meaning in whole compositionj, guna (excellences, qualities), alamkara @oetic figure), rasa (state, of being), kuraka (casa ending), kriya (verb), linga (gender or marking) vacana (number), visesana (qualification), upsarga (prefix), nipata (redundancies), kala (time, tense), desa (country), kula (family), vrata (custom), tattva (truth), sattva (mherent self), abhipriya (motive), svabhava (nature), Sara samgraha (essential properties), prdtibha (inmate ability), avastha (condition,state) vicaka (thought), namn (name), asirvada (blessings).