diff --git a/public/home/chapters/04_nachhaltig.html b/public/home/chapters/04_nachhaltig.html
index 1ccb3861e6822e2855489ff136dc6384e9e0633e..7a7eb4dcbdff38e751e5cce6196fc8815ce91848 100644
--- a/public/home/chapters/04_nachhaltig.html
+++ b/public/home/chapters/04_nachhaltig.html
@@ -1,5 +1,5 @@
<!DOCTYPE html>
-<html>
+<html lang="de">
<head>
<meta charset="utf-8">