I haven't seen any firm date announcement yet. Keep checking out
Tiger Airways news section. As soon as we'll have any information it will be posted there.
This is the latest from Tiger Airways:
Tiger Airways has been granted the rights to fly between Singapore and Chennai, Cochin, Goa, Trivandrum, Kolkata and Kozhikode. The airline is now in the midst of planning its flight routes and is in talks with airports and suppliers at these destinations. Tiger Airways will be announcing its initial route network to India once discussions have concluded, which the airline expects to take place fairly soon.