Indeed its India, Calcutta I'm talking about. True 20 years back (1996 and before.. vaguely) that's when we were children the Ganges water was clean. It is too polluted now to drink it straight away. And nobody really drinks it taking it straight from the tap. There were times when NGOs offered large earthen pots of cool water free on the streets. In my home we have a non-electric Ceramic water filter. But the current norm is electric RO +UV filters.

Arsenic is present in ground water in south Calcutta and is a health problem. Municipal water is arsenic free. It is treated with Chlorine.

Much/All of this pollution is self created by polluting the rivers. Individually, industrially and socially.

I believe that using bottled water should be an exception and availability of tap/filtered water at public places should be a norm. But bottled water has become a necessity and a fad today.

I do admire the places mentioned where you enjoy pure water still. I know that in New York the water comes from upstate reservoirs. I also think many places water fountain is available at public places/streets for drinking. If you know the cities you've seen this let me know I'll make a note of it.