They pass through India at lunchtime, and the long range ones get to the Far East for sunset next day. After turnaround and return, they get back in time to wake you up nice and early, leaving them available to epart again on the morning wave across the Atlantic. So that departure time fits in with sleep period travel both ways and convenient arrival and departure times. If you actually look at the flights on a clock scale, there's actually a very small 'window' that gives a departure time and arrival time at destination and return back at base, and ticks all the other boxes to maximise utilisation.