By this I mean the overstimulation of the senses that happens while you are there.
My answer is probably Old Delhi. From the sheer population density, the near-constant honking, the utter chaos on the streets, the panoply of religions and ethnicities, the myriad scents and colours that pass you by as you travel down the narrow lanes, and not least the choking air pollution, it is certain to keep you on edge, not necessarily in a bad way.
Are there other cities that come close to, or even surpass, this?
I have to agree with you about Old Delhi. I was constantly harassed, followed, and it just wasn’t pleasant to be there.
Beijing was similar but it’s a bit cleaner.
Havent been to Old Delhi but I found Hanoi to be quite overwhelming
Istanbul
Dhaka.
Tokyo for me
Just personally, Old Delhi was a pleasant stroll around compared to Kolkata.
Varanasi - not in a bad way, but there sure is a lot going on there!
Oh gosh. A lot of the cities in India for sure, but I would add HCMC, Manila, Cairo, Dhaka, and (Jakarta, Bangkok, Bogota). Tokyo can be a lot as well but it’s almost organized chaos vs. I feel like im going to die if I took my eyes off for a second.
No South American entries yet so I’ll throw in Salvador, Bahia, Brazil
Medellin could be overwhelming at times, particularly if you travel there solo. Wouldn’t dream of driving there (crossing the street was enough of a challenge), constantly having to watch your back for thieves, and noisy around certain districts in and near the center of the city.
Delhi
Certain parts of Mexico City at certain times
Bangkok / Cairo
Ciudad Del Este
Chicago easily or New York