I keep my windows cracked in the winter despite having control (and payment responsibility, mind) of our heating. It's worth being able to think clearly all winter: https://www.yaleclimateconnections.org/2016/07/indoor-co2-du...
With slightly open windows, you're losing a bunch of heat for very little ventilation.
In Russia, it's most likely an inverse of venue class. Malls, public venues, indoor markets, govt buildings all like to save on ventilation.