diff --git a/doc/release_notes.rst b/doc/release_notes.rst
index 5cc3422c0..3f1318334 100644
--- a/doc/release_notes.rst
+++ b/doc/release_notes.rst
@@ -46,6 +46,8 @@ E.g. if a new rule becomes available describe how to use it `make test` and in o
 
 * Fix bugs in `prepare_sector_network.py` related to links with H2 buses and bug of re-addition of H2 and battery carriers in present `PR #1145 <https://github.com/pypsa-meets-earth/pypsa-earth/pull/1145>`__
 
+* Drop entries that contain non-string elements in country column of `CO2_emissions_csv` data in `prepare_transport_data_input.py` script `PR #1166 <https://github.com/pypsa-meets-earth/pypsa-earth/pull/1166>`_
+
 PyPSA-Earth 0.4.1
 =================
 
diff --git a/scripts/prepare_transport_data_input.py b/scripts/prepare_transport_data_input.py
index a15608adc..d932d1174 100644
--- a/scripts/prepare_transport_data_input.py
+++ b/scripts/prepare_transport_data_input.py
@@ -93,14 +93,17 @@ def download_CO2_emissions():
     # Add ISO2 country code for each country
     CO2_emissions = CO2_emissions.rename(columns={"Country Name": "Country"})
     cc = coco.CountryConverter()
-    Country = pd.Series(CO2_emissions["Country"])
-    CO2_emissions["country"] = cc.pandas_convert(
-        series=Country, to="ISO2", not_found="not found"
+    CO2_emissions.loc[:, "country"] = cc.pandas_convert(
+        series=CO2_emissions["Country"], to="ISO2", not_found="not found"
     )
 
     # Drop region names that have no ISO2:
     CO2_emissions = CO2_emissions[CO2_emissions.country != "not found"]
 
+    # Drop region names where country column contains list of countries
+    CO2_emissions = CO2_emissions[
+        CO2_emissions.country.apply(lambda x: isinstance(x, str))
+    ]
     return CO2_emissions