Consider the Benefits of Accepting a Transfer
There are three answers to your query that are sufficient to clarify your situation and options. The purpose of my writing is different. I assume you are not in the Class IV (Peon or Messenger) category. The question is, why should you decline a transfer? You have been with the bank for just one year, and they have considered you for a promotion. By declining, you are creating a "negative" for yourself.
You should know that in several professions, people are transferred every 2-4 years—from defense services to IAS/IPS/Construction Projects, banks, and many other departments. People move. It appears you are young. You should be prepared to go anywhere. If your wife is also working, then you need to take a call on who will adjust. Moving to new places enlightens you, broadens your thinking, and adds to your experience. Don't create or imagine flimsy reasons for not going out of Pune. Come out of your comfort zone and take the challenge. Else, be satisfied with a below-average career.
I don't know which location you are being transferred to. But suppose you were transferred to the bank's London or Tokyo branch. Would you have declined for the same "personal" reasons? Most likely, no. Even if it is a rural posting, you should still accept it. Somebody has to serve the rural population too. If everyone declines, then who would go there? If soldiers decline to go to Siachen or Kargil, what will happen? I strongly suggest accepting the transfer and going happily with pride.
Regards