I found an interesting image of an art based on a fresco and relief with AI. Below I will leave other references that are unclear but seem convincing. 

Oops! You are certainly right! Sorry for the confusion!

These clothes, it seems to me, resemble those from Central Asia and Hellenized areas of India.  Hellenistic India. Kushan art. The trousers bear a certain resemblance. Probably an influence from Iranian peoples.

https://archeologie.culture.gouv.fr/palmyre/en/clothes-and-jewellery     Men wore embroidered baggy trousers and belted long-sleeved tunics. Women generally wore a tunic, a mantle fastened on the left shoulder with a fibula, earrings, one or more necklaces, bracelets, a brow band often decorated with plant motifs, a turban and a long veil. A preference for an Iranian garment or a Greek mantle was a matter of taste, wealth or mood, not of origin or profession. The central role played by Palmyra in trade between the Mediterranean and the East made it one of the main stopping points for caravans transporting luxury materials such as gold, gemstones and pearls. It was also a focal point for the styles, fashions and techniques that travelled with the merchants. The Palmyreans assimilated these different influences: Palmyrene silverwork and goldwork, for example, are a rich synthesis of eastern, Roman, Greek, Hellenistic and Syrian elements and motifs.  

According to: https://history.stackexchange.com/questions/46106/what-was-clothing-in-ancient-palmyra-like   An important trading centre which derived much of its wealth from the Silk Road, Palmyra was a multi-cultural city, influenced by both east (especially Iran) and west (Greece and Rome). This is reflected in the clothing they wore, but there was also a distinctly local style; in short, it’s a complex picture and generalizing is difficult. As Marybeth Osowski, in Fashioning Identity: Clothing and the Image of the Syrian in the Roman Empire, states:   The standard visual image of the Near East in Greek and Roman depictions features elements such as long-sleeved tunics and ankle-length trousers, bright colors and elaborate patterns or decorations, and other items like pointed hats or turbans also feature but are not universal.   The best visual evidence we have of clothing in 3rd century AD Palmyra comes from funerary monuments. However, these cannot be considered entirely representative of the population as a whole but rather of the local elite and wealthier residents, most likely wearing their finest clothing. Further, we can’t be sure to what extent these may have been idealized representations of what people actually wore. Lastly, there is the issue of status, and of how people wished to be seen in different social and cultural situations.   Generally speaking, there two styles of Palmyrene attire: one is termed Greek or Greco-Roman, the Parthian or sometimes Persian. Let's go: Sassanid clothes.