diff --git a/flatland/core/env.py b/flatland/core/env.py
index 98e577897ea667f6f8f57a6f8c63561d6d5ff7ec..263ae73ca55f1191aab87436a1589af30adda693 100644
--- a/flatland/core/env.py
+++ b/flatland/core/env.py
@@ -4,9 +4,6 @@ The base Environment class is adapted from rllib.env.MultiAgentEnv
 (https://github.com/ray-project/ray).
 """
 
-# TODO: add derived classes and environments, e.g., GridEnvironment and
-# RailEnvironment.
-
 class Environment:
     """Base interface for multi-agent environments in Flatland.