The Arthaśāstra names the regions that horses were imported into the rest of mainland India from —
- prayogyānām uttamāḥ kāmboja-saindhava-āraṭṭa-vanāyujāḥ - “The best horses come from Kamboja (Persia), Sindhu (Southern Sindh), Araṭṭa (parts of Punjab?) and Vanāyu (Arabia)”
- madhyamā bāhlīka-pāpeyaka-sauvīraka-taitalāḥ - “The average horses come from Bahlīka (Bactria), Pāpā (Pāli spelling: Pāvā), Sauvīra (Northern Sindh) & Titala??”
- śeṣāḥ pratyavarāḥ - “The rest are low quality.”
Most scholars consider Pāpā and Titala to be towns/regions located in the north-west (with possible connections to Central Asia along the silk road) since North-Eastern India has no history of horse breeding, much less exporting them to other locations.
Alexander’s war against the Mallas happened in the Punjab (between the Hydaspes i.e. Vitastā river and the Acesines i.e. Asiknī) - and it appears that the Oxydraci (i.e. Kṣudrakas) allied with the Mallas against Alexander. Perhaps the western city of Pāpā was in this territory - as the Pāli canon also implies that the Pāveyyaka bhikkhus are westerners (and who are contrasted with the pācīnaka i.e. “eastern” bhikkhus – “adhammavādino pācīnakā bhikkhū, dhammavādino pāveyyakā bhikkhū”ti and again at sammatā saṅghena cattāro pācīnakā bhikkhū, cattāro pāveyyakā bhikkhū)
Moreover most Jains (and their oldest and holiest pilgrimage sites) have been concentrated in Western India since antiquity. Here is a map of their current population-density. Jainism in India - Wikipedia - which I also shared earlier. If Pāvā was the place where Mahāvīra (i.e. Nirgrantha Jñātiputra) died, it would make sense to assume that he lived and died in a region where most of his followers were located i.e. Western or North-Western India.
