Answer by Amandeep Gautam:
The suffix is not "bad", it is "abad" as in Hyderabad, Ahmedabad, Secunderabad, Allahabad etc. The meaning of "abad" in Urdu is "The area or environment where an organism or ecological community normally lives with reference to the name".
You can relate to the fact that these cities were ruled by Muslim rulers in recent past or maybe dominant Muslim population(using Urdu for daily use) and it is where the influence of Urdu comes in.
You can find similar suffixes in cities like Bharatpur, Jaipur and many more where Hindi is widely spoken and pur in Hindi means "city" or "settlement".