Why there is always around a horrible smell of sweat in Poland

That's what a bar of soap and deodorant prior to and afterwards are for while going out in public in the summer dude.
Sweat doesn't stink, three day old sweat stinks.
No excuse for pis poor hygienics besides just being lazy, having no self respect or pis poor parenting.
And it ain't just Poland with this low life mentality.

That's why you need to take a shower in the morning.

@Alien
Right now, morning AND night. It's been humid AF out here in Warsaw. If someone isn't bathing at all during this period, they're a straight-up terrorist and should be arrested.

At 35°C it is Ok.

Save water, shower with a friend.

Brits hate Yank tourists because Yanks use a month-worth of water in the first three days or sooner...

No they don't