Languages

Read, write and listen more. Nothing like learning you can learn it by your own way.

It depends on the educational institutions, but most probably English is the teaching medium.

As per my knowledge, JNU is best.

Dear Swati,
Check the below link there are 36 colleges in India matching your requirements. You can see more about the college, ranking, fee structure and other details.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/humanities-social-sciences/languages/colleges/japanese-colleges-india&ved=2ahUKEwj1tbvb1MLiAhXBjOYKHSM7DvYQFjAAegQIAxAB&usg=AOvVaw22aTarY6McpDMJqRMxC-6c

You can check their website. It must be mentioned on the admissions page.

Most colleges only have objective type question papers.

You should go through Indian and Japan history and diplomatic relations.

Yes, there are some chances to get admission in DU so apply for admission. Good luck.