Top products from r/BuildingCodes

If they renovate a residential building the builder is required to ventilate it then. New buildings must build in ventilation in bathrooms at time of construction. Bathrooms in existing residential buildings aren't required to retrofit.

I've used these https://www.amazon.com/gp/offer-listing/B0007N5LHM/ref=dp_olp_0?ie=UTF8&condition=all

Just from a functional standpoint, you would want the mechanically exhausted option. While windows are allowed, they generally don’t exhaust enough air to reduce humidity levels - particularly when it’s already humid outside, and in your situation where there’s air in a limited exterior space so breezes or drafts are unlikely. Also, if the bathroom has no supply air, the window is even more useless, as there’s no positive air pressure in the bathroom to force air out the window.

Least expensive solution: put a through-wall vent above the window. Something like this small vent..

Not sure how you work it out with landlord; but technically, if you do upgrades, it has to meet the current code, so you can argue this costs (much) less than installing a larger window, and will work better.