diff --git a/definitions/variable/tag_credits_projects.yaml b/definitions/variable/tag_credits_projects.yaml
new file mode 100644
index 0000000..936c26b
--- /dev/null
+++ b/definitions/variable/tag_credits_projects.yaml
@@ -0,0 +1,9 @@
+- Project Category:
+    - Conventional CDR:
+        description: conventional carbon dioxide removal methods
+    - Novel CDR:
+        description: novel carbon dioxide removal methods
+    - Mixed (Mainly CDR):
+        description: mainly CDR methods, but also including avoided emissions
+    - Mixed (Mainly Avoided):
+        description: mainly avoided emissions, but also including CDR methods
diff --git a/definitions/variable/variables.yaml b/definitions/variable/variables.yaml
index 1074fc8..e54e5c3 100644
--- a/definitions/variable/variables.yaml
+++ b/definitions/variable/variables.yaml
@@ -133,6 +133,13 @@
     description: Amount of investment in start-ups related to {Conventional CDR Method}
     unit: billion USD
 
+- Carbon Credits|Active Projects:
+    description: Number of active projects in the voluntary carbon removal market
+    unit:
+- Carbon Credits|Active Projects|{Project Category}:
+    description: Number of active projects in the voluntary carbon removal market
+      that use {Project Category}
+    unit:
 - Carbon Credits|Novel CDR|Tons Sold:
     description: Credits sold (purchased) in the voluntary carbon removal market
       using novel CDR methods, measured in terms of carbon removed