UPSC/IAS Mains Exam Indian Language Paper (Compulsory)
Assamese	Bodo	Hindi
Maithili	Marathi	Oriya
Sanskrit	Tamil	Urdu
Bengali	Gujarati	Kannada
Malayalam	Nepali	Punjabi
Santhali	Telugu	English

UPSC 2016 Civil Services Mains Exam Optional Subjects Paper
Agriculture Paper I	Animal Husbandary & Veterinary Science Paper I Anthropology Paper I	Botany Paper I	Zoology Paper-II
Chemistry Paper I	Civil Engineering Paper I	Commerce & Accountancy Paper I	Economics Paper I
Electrical Engineering Paper I	Geography Paper I	Geology Paper I	History Paper I
Law Paper I	Management Paper I	Mathematics Paper I	Mechanical Engineering Paper I
Medical Science Paper I	Philosophy Paper I	Physics Paper I	Political Science & Internation Relations Paper I
Psychology Paper I	Public Administration Paper I	Sociology Paper I	Statistics Paper I
Zoology Paper I	Agriculture Paper-II	Animal Husbandary & Veterinary Science Paper-II	Anthropology Paper-II
Botany Paper II	Chemistry Paper II	Civil Engineering Paper II	Commerce & Accountancy Paper II
Economics Paper-II	Electrical Engineering Paper II	Geography Paper-II	Geology Paper II
History Paper-II	Law Paper-II	Management Paper-II	Mathematics Paper II
Mechanical Engineering Paper II	Medical Science Paper-II	Philosophy Paper-II	Physics Paper II
Political Science & Internation Relations Paper II	Psychology Paper-II	Public Administration Paper-II	Sociology Paper-II
Statistics Paper II

Also read-

UPSC 2017 Question Papers

UPSC 2016 Civil Services IAS Mains Exam Literature Subjects Paper (Optional)
Assamese Paper I	Bengali Paper I	English Paper I	Gujarati Paper I
Hindi Paper I	Kannada Paper I	Manipuri Paper I	Maithili Paper I
Malayalam Paper I	Marathi Paper I	Oriya Paper I	Punjabi Paper I
Sanskrit Paper I	Santali Paper I	Sindhi (Devanagari) Paper I	Tamil Paper I
Telugu Paper I	Urdu Paper I	Assamese Paper-II	Bengali Paper-II
English Paper-II	Gujarati Paper-II	Hindi Paper-II	Kannada Paper-II
Manipuri Paper-II	Maithili Paper-II	Malayalam Paper-II	Marathi Paper-II
Oriya Paper-II	Punjabi Paper-II	Sanskrit Paper-II	Santali Paper-II
Sindhi (Devanagari) Paper-II	Tamil Paper-II	Telugu Paper-II	Urdu Paper-II