That 1 HD too replacement not addition so its more or less sure by that way.
There may be delay in securing a deal with Broadcasters and this is good for Airtel too they may get at a lower price.
Maximum one year delay is very usual in Airtel SAB HD faced a worst delay among Hindi GEC in recent times upto 1 year it got delayed.
For a ROI GEC if that's the case then we cannot expect other Genres/Regional HDs pretty soon on Airtel unless its from very influential Networks like Star which were given on free preview basis to Operators.