diff --git a/envs/environment.fixed.yaml b/envs/environment.fixed.yaml
index cde31ba2..72339219 100644
--- a/envs/environment.fixed.yaml
+++ b/envs/environment.fixed.yaml
@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: : 2017-2022 The PyPSA-Eur Authors
+#
+# SPDX-License-Identifier: CC0-1.0
+
 name: pypsa-eur
 channels:
   - bioconda