This is a challenging question. Businesses that deal with controlled substances such as alcohol are often governed by local laws and regulations. The specific requirements for Kolkata will differ from those in other parts of the world and will impact start-up costs accordingly.
For example, here in the U.S., a new bar must apply for a license to serve alcohol. The application process and associated costs vary from State to State. Also, there may be regulations that impact where your business is located that will impact your costs. Employing training and/or certification may also be an expense that you need to consider.
You should be able to determine these rules and regulations by contacting someone locally in Kolkata. If you are uncertain as to where to begin, you could interview an existing bar owner to gather their thoughts and experience. That may be a very good place to start.