Searched the rules and cannot find an answer to this problem :-
What happens when it comes your turn to place a tile and it is impossible to play it legally, the example we had was round 3 of our game (2 player) the edges to build against were mainly farmland with some water and only one forest edge, my opponent took a tile to exploit the forest but I closed it down leaving them nowhere to play their tile (it was forest and mountain).
We came up with 3 possible options :- 1. The player misses a turn. 2. The next player (in our case the opponent) chooses a face up tile for them to play. 3. The next player chooses a face down tile for them to play.
In all cases they keep the unplayable tile to be played on their next turn.
We went with 3 as the least punishing whilst giving a little influence to the next player with regards to losers bonuses on the backs of the tiles, but is there an official answer which I have missed somewhere?
This can happen, even if it is rare and usually happens on the first turns. My suggestion is that the player who cannot play the tile, shows the tile to the other players demonstrating the impossibility of playing it. The he chooses one tile face up from the display and plays that one. The tile the could play is discarded on the bottom of the same stack he drew the face up tile he actually played.
To recap: if you cannot play one tile, discard that tile and choose another tile face up.