After I reached a certain point in the game, deleting a used tile would erase the buildings. However, the tile itself would still contain the placeholder for what that tile used to be (C/R/etc.). Here's a screenshot of a bulldozed residential area that is 'clear' when queried:
After I reached a certain point in the game, deleting a used tile would erase the buildings. However, the tile itself would still contain the placeholder for what that tile used to be (C/R/etc.). Here's a screenshot of a bulldozed residential area that is 'clear' when queried: