In my simple thinking, there's no excuse for running out of fuel, that's why these planes have computers that figure out all these things before takeoff - even if the weather changed so dramatically en route that they flew at rooftop level for the whole distance.
The plane was from Delhi. Not sure when that route commenced, but assuming it's still a young route to be matured, they should put Embraers on it, they have the range.
38 pax is disappointing. KQ B738 are configured for 145 pax, best case scenario is the outbound was 100%, which gives the route 63% which is below break even of 70%, unless they have deployed larger aircraft for cargo reasons.
If not cargo, they should consider scrapping Delhi and code sharing from Mumbai.