diff --git a/run.sh b/run.sh
index fdef05b..8137dab 100755
--- a/run.sh
+++ b/run.sh
@@ -70,7 +70,7 @@ if [ "$1" == "import" ]; then
     if [ -n "${DOWNLOAD_PBF:-}" ]; then
         echo "INFO: Download PBF file: $DOWNLOAD_PBF"
         wget ${WGET_ARGS:-} "$DOWNLOAD_PBF" -O /data/region.osm.pbf
-        if [ -n "$DOWNLOAD_POLY" ]; then
+        if [ -n "${DOWNLOAD_POLY:-}" ]; then
             echo "INFO: Download PBF-POLY file: $DOWNLOAD_POLY"
             wget ${WGET_ARGS:-} "$DOWNLOAD_POLY" -O /data/region.poly
         fi