OK. Let me tell the reason of this offer once again.
Tata Sky has been doing preliminary tests till now. and Finally they are now all set for migration of Satellites. I have no idea they are migrating on which satellite but they have scheduled 20 days for migration.
So, to compensate any untoward signal failure in between this, Tata Sky has decided to open all Channels for all Active Subscribers.
Free channels is just an eyewash and temporary happiness. Real happiness is about to come once migration will be completed i.e from 1st June 2015