I found the below details in the D2H website.
Declaration under Regulation dated 03.03.2017
1. The total channel carrying capacity (in terms of number of standard definition channels)-
-->616
2. Number of channels for which signals of television channels have been requested by Dish TV from broadcasters under Interconnection Regulation dated 03.03.2017 and the interconnection agreements signed
--->NA
3. Spare channel capacity available on the network for the purpose of carrying signals of television channels (in terms of number of standard definition channels)
--->NIL
4. list of channels, in chronological order, for which requests under Interconnection Regulation dated 03.03.2017 have been received from broadcasters for distribution of their channels, the interconnection agreements have been signed and are pending for distribution due to non-availability of the spare channel capacity
--->NA
Meaning no more space in D2H to add channels ?