Air India:
Always possible and BHX flights have not been pulled by the
airline, suggesting a possible confidence that AI has in UK non-London airports. MAN doesn't have the same Indian VFR traffic as BHX, but perhaps there is sufficient business links to make a Delhi flight viable and there is no direct competition
Its worth noting the O&D between MAN and DEL is actually larger than BHX-DEL. BHX's main India draw is ATQ, and given DEL is attracting about 60% loads seems to confirm what the CAA stats show.