diff --git a/ProcessLib/TES/TESProcess.cpp b/ProcessLib/TES/TESProcess.cpp
index eb07ef3edd5a57083807d887cbb7545dbd04c85b..8e29d55cd4c8cc27278bb84bf027fc5b86b9b8e2 100644
--- a/ProcessLib/TES/TESProcess.cpp
+++ b/ProcessLib/TES/TESProcess.cpp
@@ -194,7 +194,6 @@ void TESProcess::initializeSecondaryVariables()
                 return computeVapourPartialPressure(args...);
             },
             nullptr});
-    namespace PH = std::placeholders;
     add2nd("relative_humidity",
            {1,
             [&](auto&&... args) -> GlobalVector const& {