Probably a lot of the fabrication/integration work. The DRDO actually are very good at armoured vehicle suspension/hydraulics and such. TATA probably provided the FCS.
It seems like a pretty good machine- this must be part of TATA's F-ICV bid. They really are hungry for this deal. Good on them, hopefully this project gets its act together and makes some moves soon.
I hope TATA is going about this properly and looking at such ICV's contemporaries and will be making a family of ICVs i.e. ambulance, mortar carrier, CBRN, recovery etc variants then I will really be interested.