Commerce

Hi Madhurjya,
Don't think that way. There are a lot of Assamese people in Delhi too.
I'm an Assamese and I'm pursuing B.Com (Hons) from SRCC, Delhi University. It's absolutely fine and normal for you to take admission in any college you want and anywhere in the world.
And talking about the communication, Delhi has a mixture of people from all parts of the country. Hindi and English are the two languages mostly used here.

Yes, it's enough. If you are interested, you can go for higher studies.

Yes, it is compulsory to get passing marks in maths. But it's not compulsory to add it in your best four percentage.

Yes, you can be an upper primary teacher.

Yes, it is possible but you have to do hard work because after two years you have to face maths which will be difficult for you.

It is clearly mentioned in the guidelines of Delhi University that you can't opt for economics (Hons) if you haven't studied maths till 12th. You can't opt B.Com (Hons) too but you can go for B.Com programme.