Surroundings; congealing (7)
I believe the answer is:
setting
I believe this clue is a double definition.
'surroundings' is the first definition.
(setting is a kind of surroundings)
'congealing' is the second definition.
('set' can be a synonym of 'congeal')
(Other definitions for setting that I've seen before include "Compiler's job" , "Gem''s mounting - stage scenery" , "approaching the horizon" , "Dropping beneath the horizon" , "An event's location; hardening" .)