Bittorent is a legal service. The contents of shared files via bittorent might be illegal, but bittorent, in of itself, is legal. Open source  software for instance,  are being distributed through it. If the ISP decide to throttle the software itself, while  the user had not exceed its monthly quota bandwidth, then the ISP is not adhering to its own fair usage policy. I could understand that P1 Wimax feels the need to limit its bandwidth usage, but doing the throttling before users exceed the given bandwidth quota can be considered as a breach of trust, if not breach of agreement more so.

The term and agreement explicitly stated that users are given a certain quota of bandwidth to use, and if the the bandwidths are being used up before the end of the month, then ISP have the right to impose a traffic throttling.

Another clause in the terms and agreements  is that the service is being provided at "best effort" basis. I don't quite remember the details, but "best effort" basis means that the ISP should provide the speed not slower than the 70% of the advertised speed. I think thats the guideline laid down by MCMC.

Regardless of the legality of the contents, bittorent is a legal service. As such, the ISP that throttling bittorent deprive its user on their overall internet experience and can be deemed for not providing its internet service at "best effort" basis.