If UA1kMFR doesn't want to fly the likes of AI, (s)he probably wouldn't care to fly from BOM-DEL via the remaining options, such as IC, 9W, or S2!

Another option is to take SQ JNB-SIN-DEL. That is probably the most direct *A route on a decent carrier. The only downside is a 12-hour layover in SIN. Via BKK, you're looking at three flights, such as SQ/SQ/TG. Note that the TG BKK-DEL flight leaves in the evening (I'm on it tomorrow), which is another layover. The only earlier flights are AI and IC.