diff --git a/docker/NBI/Dockerfile b/docker/NBI/Dockerfile
index 3b50256..4ac2a49 100644
--- a/docker/NBI/Dockerfile
+++ b/docker/NBI/Dockerfile
@@ -48,7 +48,8 @@
 FROM ubuntu:18.04 as FINAL
 
 RUN DEBIAN_FRONTEND=noninteractive apt-get --yes update && \
-    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.6.*
+    DEBIAN_FRONTEND=noninteractive apt-get --yes install python3-minimal=3.6.* \
+    && rm -rf /var/lib/apt/lists/*
 
 COPY --from=INSTALL /usr/lib/python3/dist-packages /usr/lib/python3/dist-packages
 COPY --from=INSTALL /usr/local/lib/python3.6/dist-packages  /usr/local/lib/python3.6/dist-packages