Blocker
Concept · Colony · Stellaris 4.5.2
Blocker (colony) in the Stellaris encyclopedia: A Blocker is a planetary feature that obstructs other features or prevents certain Districts from being constructed on a Colony.
Blocker in the game's words
The encyclopedia entry as the game shows it in its tooltips; underlined words open their own entry or page here.
A Blocker is a planetary feature that obstructs other features or prevents certain 
Districts from being constructed on a 
Colony.
Some Blockers can be cleared at a resource cost, often requiring specific Technologies. They are managed in the 
Colony View.
Entries that mention Blocker
More in Colony
Source: common/game_concepts (concept_blocker, also concept_blockers) and localisation/english, Stellaris Cygnus v4.5.2 (9776).