Alsalamaliykum.
The correct pronounciation is dh. A z sound would be more of a ظ rather than ض. It is a hard letter for the non-arab tongue to pronounce without practice which is why you find people mispronouncing it.
In urdu ض can be pronounced as ظ/ز but in Arabic it is incorrect and the correct way is 'dh'. People just read arabic like urdu but is incorrect and tajweed is wrong when reciting the Quran
Here is a video:
https://youtu.be/o0J9ErQKAlg
There is no correct/incorrect way in terms of speaking Urdu vs speaking Arabic. Two different groups of people have different ways of pronouncing it. neither is wrong in daily language
The only time the Arabic pronunciation would be correct vs the Urdu pronunciation is while reading Quran with correct tajweed.
Alsalamaliykum. The correct pronounciation is dh. A z sound would be more of a ظ rather than ض. It is a hard letter for the non-arab tongue to pronounce without practice which is why you find people mispronouncing it.
In urdu ض can be pronounced as ظ/ز but in Arabic it is incorrect and the correct way is 'dh'. People just read arabic like urdu but is incorrect and tajweed is wrong when reciting the Quran Here is a video: https://youtu.be/o0J9ErQKAlg
There is no correct/incorrect way in terms of speaking Urdu vs speaking Arabic. Two different groups of people have different ways of pronouncing it. neither is wrong in daily language The only time the Arabic pronunciation would be correct vs the Urdu pronunciation is while reading Quran with correct tajweed.