MTNL provides approx 2 Mbps speed on most of the 256kbps lines.
This is because they are lazy enough to work on it although it's a boon for we customers. At times the speed reduces to approx 256 kbps or less and this thing continues for a few hours to 1-2 days. This is normal and don't panic as it gets resolved automatically. But let me tell you that I tried Open DNS twice and the issue was resolved and so I checked back by using no DNS or MTNL DNS and the speed was fine at that time. It might be coincidence or this might have worked but try this work around.

unk:
OpenDNS provides the following recursive nameserver addresses for public use, mapped to the nearest operational server location by anycast routing:
To learn more about OPEN DNS copy thes URLs in the address bar
- opendns.com/start
- en.wikipedia.org/wiki/OpenDNS