diff --git a/Lib/zoneinfo/_common.pyold b/Lib/zoneinfo/_common.py
index 98cdfe37..75f8fd2b 100644
--- a/Lib/zoneinfo/_common.py
+++ b/Lib/zoneinfo/_common.py
@@ -11,6 +11,12 @@ def load_tzdata(key):
     try:
         return resources.files(package_name).joinpath(resource_name).open("rb")
     except (ImportError, FileNotFoundError, UnicodeEncodeError):
+        import sys
+        if "tzdata" not in sys.modules:
+            raise ZoneInfoNotFoundError(
+                f"No time zone found with key {key}. \n"
+                " On Pyodide you must do pyodide.loadPackage('tzdata')"
+                " package before you use zoneinfo.")
         # There are three types of exception that can be raised that all amount
         # to "we cannot find this key":
         #