Baghdad is on the list with an erroneous spelling. But New Delhi's absence from the list is justified as the National Capital Region (New Delhi) has a moderate population. Not to be confused with the greater metropolitan Delhi, which the NCR is a part of.
I am assuming this is based on population of the city proper, rather than on the metropolitan area, though this should be specified. Also, please fix the spellings of Baghdad, Tehran, and Pyongyang, as I missed these three solely due to spelling.