TRAI had recently directed the telecom operators to ensure a minimum 512 kbps download speed at all times but Bharti Airtel, Reliance Communications and Sistema Shyam Teleservices have objected to the directive.
The reason telecom operators are citing is that once a customer have exhausted the data limit, the service providers should be allowed to provide 64 kbps. Both Reliance and Airtel have cited a similar reason in its submission to the regulator.
Sistema Shyam Teleservices in its submission said that 512 kbp speed should be provided till the consumption of committed data under a tariff plan, beyond which throttling should be allowed to avoid exploitation or misuse by subscribers.
[source]