diff --git a/map_gen/misc/nightfall.lua b/map_gen/misc/nightfall.lua
index f5a49cfb..bd98158c 100644
--- a/map_gen/misc/nightfall.lua
+++ b/map_gen/misc/nightfall.lua
@@ -32,6 +32,7 @@ local lastattack
 local c_index
 local random = math.random
 local insert = table.insert
+local get_pollution = game.surfaces[1].get_pollution
 
 local function biter_attack()
     local maxindex = #bases
@@ -90,7 +91,7 @@ local function find_bases()
             state = ATTACKING
             break
         end
-        if game.surfaces[1].get_pollution(chunklist[i]) > 0.1 then
+        if get_pollution(chunklist[i]) > 0.1 then
             local chunkcoord = chunklist[i]
             if (game.surfaces[1].count_entities_filtered{area={{chunkcoord.x-16, chunkcoord.y-16},{chunkcoord.x+16, chunkcoord.y+16}},
                     type = "unit-spawner"}) > 0 then