You can always use the +- UTC at the bottom if you happen to know yours.
I don't. Not for Mumbai or Barcelona. And I can't think of any other big cities near those. In the US you usually see GMT instead of UTC, but I guess UTC is more politically correct or something. And you apparently want to be inclusive towards the Antarcticans.
type the nearest large city and it will scroll to it
It doesn't. It only scrolls by first letter. So if you start typing Barcelona, you get Barnako, Adak, Rainy River, Casey, Eucla, LHI, Oslo, Naura, Abidjan in sequence.
I can Google my way around it, but the point is that the timezone dropdown is a piece of crap and needs to be fixed.