Via the MetaFilter Archie thread that keeps on giving: Harry Potter and the Eurocentrist's Tone.

What is worse is the costume of the Asian women. Cho, Padma, and Parvati Patil wore "garb" to the Yule Ball. What were described in the book as "shocking pink dress robes" become a sari for the twin Indian girls, and a cheongsam for Cho. These girls are not, like Viktor or Fleur, actually nationals of other countries; they are English, and I found myself totally abandoning suspension of disbelief when they showed up to dance in the sort of clothes I think teenagers of all stripes are known for avoiding: the ones that connote traditionalism and otherness. It's not like we need the extra cultural artifacts to figure out their Asian status. It was totemization and exoticism, plain and simple. Boo.

The Patil sisters are treated in a fairly objectified manner in book and film alike, with little said about them other than that they are the prettiest girls in their year. Their twinness is also a little unnerving as it leads me to thoughts of indistinguishability and male fantasy. Additionally, Parvati is, to my knowledge, the only character to have been portrayed by different actors in different films (aside from Dumbledore, played by Richard Harris, who passed away) which certainly casts a pall of indistinguishability over her. The IMDb entry for the two films in which she is portrayed by different actors also lists her name with different spellings... Patil and Patel. I'm not sure who to blame for that.