I am assuming you mean DEL and not DEI.
For traveling to DEL, I would go CLT-LHR-DEL. It's an easy 2.5 hour connection, arriving at LHR at 8 am and leaving at 10:30 am. Coming back from BLR is a little more complicated because the BA flight arrives too late to make a LHR-CLT flight. So, you will have to make 2 stops unless you want to spend ~21 hours in London. BLR-DOH-ORD-CLT on Qatar/AA or BLR-HKG-ORD-CLT on Cathay/AA are your two best options.