Yeah the Emirates schedule shows a daily flight from DXB-DEL. Maybe the flights are full on the other 4?
Btw..when you're flying out of DEL, try to go to the airport early. I remember I went there 3 hours before the flight time and the queue was very long and for some reason the check-in counters wasn't open yet. I remember the queue was very very long...too long for that matter. I think I took a video of the queue after I checked in, I could try to find it for you if you're interested.