Yes! UPSC allows the candidate to appear for the GS papers & the optional papers to be in different medium. So if you wish to write your GS in english & the other papers in Hindi then also its possible.
For more information regarding UPSC CSE you can consider visiting the link below:
https://competition.careers360.com/exams/upsc-civil-services-exam
I hope this helps. Wish you a great day!
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