Hello
the UPSC IAS Prelims Exams has a question paper which contains questions of the objective type, so in that there are only two languages availably, English and Hindi. But for the UPSC Mains Exam you can answer in Kannada language as it is accepted by UPSC, however the questions will be given in English or Hindi language, hence it is required that you have minimum knowledge in these language.
You can check all the details regarding UPSC from the link below
https://competition.careers360.com/articles/upsc-ias-application-form
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