Hii!
Yes, the exam is conducted in English language mode only. Now, if you want to improve your language, you can start solving previous year question papers and trying to understand the way the questions are asked in the exam. Also, to improve in long term basis, start reading english newspapers, out loud. Try talking in English. Read books to improve your vocabulary. Because, you can only learn if you try and practice.
Hope this helps.
Good luck!