I don't think that ur ISP is throttling ..... I am using Airtel with no problems.
Also there is no specific news of BSNL throttling bittorrent data.

- Goto and post a screen shot.
- Are your ports forwarded ?? are u connectable ??
- Do u employ any kind of IP banner/filter .
- Do u get similar speeds for all sorts of torrents ... i mean from different places.