How can I track currently available maps

Solution 1:

The Rotation will happen every month with 4 maps getting in the Map Pool and 4 maps get out of it. This was introduced, with the reduction to 14 maps in the Casual Map Pool and 12 in the Ranked and Unranked Map Pool, with the new Ember Rise Season.

The current Ranked Map Pool are:
Canal, Oregon, Clubhouse, Consulate, Bank, Chalet, Kafe Dostoyevsky, Border, Skyscraper, Coast, Villa, Outback.

In the Casual pool this are included to and the following are being added:
House, Plane, Favela, Tower

Removed are the following:
Skyscraper, Hereford, Fortress, Chalet

These are the links to the Announcments:
Current Map rotation
Patchnotes to Ember Rise important part at Map Rotation

To keep track of it you should visit the Rainbow 6 Siege Home page after every update, since there isn't any an ingame Announcment on Map Pool Changes, and look in the News Section for Map Pool Changes.