Basically Most of the Companies have package classification as ROI and South..... What airtel has done is with 40 Channels Max HD pack, they have added ROI regional channels into this pack i.e. 3 Bengali and 2 Marathi....
For those quoting Colors Kannada, its is not part of this pack and currently available as free preview !!
None of the south Indian Channel is part of this pack as of now i.e. Tamil (Sun TV & Sum Music), Telgu (Gemeni TV), Malayalam (MM HD & Asianet HD) and Kannada (Colors Kannada HD).....
Also in addition may be Colors and Star are providing these regional channels as complimentary for some time before launching on other DTH platforms to promote HD for Regional Market.....
I am still getting Asianet HD on my STB.....