Hello Shubham, 

The topic is not related to only Banglore colleges its with most of the colleges across the country. Its because there should be no duplicacy. You will get all the documents after your graduation and it varies from college to college.

I hope you will find my answer helpful. 

All the best. 

Hello Shubham. Not only in Bangalore but everywhere in India original documents are to be submitted during admission. You will get all your documents back such as birth certificate, domicile, marksheets, etc when you will leave the college after 4 years. All your documents will be returned back to you except your leaving of the previous institute as you will be getting the leaving of this institute after your graduation.