diff --git a/ci/readthedocs/environment.yml b/ci/readthedocs/environment.yml
index 971d1b8..8b9eb76 100644
--- a/ci/readthedocs/environment.yml
+++ b/ci/readthedocs/environment.yml
@@ -1,7 +1,6 @@
 name: numkit
 channels:
 - conda-forge
-- defaults
 dependencies:
 - python=3.11
 - numpy>=1.0