Download Remote Location NAS Data

I am guessing that you don't have a corporate network though, otherwise Mumbai could directly access your ReadyNAS.

If the Mumbai branch also has a ReadyNAS you could use an rsync backup job to regularly copy a share to the Mumbai ReadyNAS.  This will not transfer data using ReadyCloud servers, so the performance will depend only on the network connection between the branches.

Start with this guide:  http://kb.netgear.com/29741/How-do-I-back-up-data-between-two-ReadyNAS-OS-6-systems-using-the-backup-manager  

If you are needing to transfer the data over the internet, you will want to adapt the guide above to use rsync over ssh instead.  This guide might be helpful: http://kb.netgear.com/29929/ReadyNAS-OS-6-Setting-up-a-backup-job-with-rsync-over-SSH (you should also read the first one, since most of the information there applies).

Another approach is to allow the Mumbai branch personnel to access your ReadyNAS using encrypted FTP (FTPS).  There are several good FTP clients that support this, including FileZilla.

If you are doing this over the internet, all these approaches will require forwarding some ports in your firewall to the RN102.  There are important security considerations there, especially when you are dealing with confidential banking records.  One way to avoid these concerns is to deploy a VPN router at both sites, which would give each site access to the other's network (using an encrypted connection).