The telecom regulatory authority of India has finally announced that the broadband speed in India is 512 kbps! The notification released by the TRAI defines the quality of broadband service as a data connection that can offer minimum download speed of 512 kbps to individuals from the point of presence aka POP. [#-Link-Snipped-# PDF].
The earlier broadband policy, formed back in 2004 defined the broadband speed in India at a minimum threshold of 256kbps.
If you aren't getting a minimum of 512kbps from your 'broadband' service provider, you should be able to file complaint with TRAI.