As much as I could gather about port forwarding is that it helps in increasing speed by efficiently using the bittorrent technology of sharing and downloading from every peer and not just from actual owner. The problem in not being able to have port forwarding could be that you wont be able to connect to all the peers. This is so because you would be able to initiate the connection to the peers, but since the ports are not configured, they wont be able to connect to you. Also, maybe some trackers wont work for you. It means that download speeds might suffer. Thats why it is important and almost every torrent client shows it. In azureus, it appears as "dht firewalled" or "NAT error". In utorrent it appears next to downloads as yellow icon. If all is well, it is green.
But it seems that it is for those who have routers in between so that router knows where to transmit the received packet from the internet. And routers for airtel gprs are with AIRTEL and they are fools enuff to not know how to configure it or maybe they are saving their bandwidth.
I just hope what all I've said is correct. By the way, I got this information from
*www.azureuswiki.com/index.php/Port_forwarding
Anyways, both azureus and utorrent are working now. Maybe they just needed a touch from Digit forums. utorrent performs a bit better for me.
Anyone with better knowledge may please verify what all I said.