diff --git a/pollution-module/data.lua b/pollution-module/data.lua
index 358a6b1..da9d6cb 100644
--- a/pollution-module/data.lua
+++ b/pollution-module/data.lua
@@ -1,10 +1,6 @@
 local item_sounds = require("__base__.prototypes.item_sounds")
 
 data:extend({
-    {
-        type = "module-category",
-        name = "pollution"
-    },
     {
         type = "module",
         name = "pollution-module",
@@ -12,7 +8,7 @@ data:extend({
         icon = "__pollution-module__/graphics/icons/pollution-module-1.png",
         subgroup = "module",
         color_hint = { text = "E" },
-        category = "pollution",
+        category = "efficiency",
         tier = 1,
         order = "d[pollution]-a[pollution-module-1]",
         inventory_move_sound = item_sounds.module_inventory_move,
@@ -35,7 +31,7 @@ data:extend({
         icon = "__pollution-module__/graphics/icons/pollution-module-2.png",
         subgroup = "module",
         color_hint = { text = "E" },
-        category = "pollution",
+        category = "efficiency",
         tier = 2,
         order = "d[pollution]-b[pollution-module-2]",
         inventory_move_sound = item_sounds.module_inventory_move,
@@ -58,7 +54,7 @@ data:extend({
         icon = "__pollution-module__/graphics/icons/pollution-module-3.png",
         subgroup = "module",
         color_hint = { text = "E" },
-        category = "pollution",
+        category = "efficiency",
         tier = 3,
         order = "d[pollution]-c[pollution-module-3]",
         inventory_move_sound = item_sounds.module_inventory_move,