diff --git a/README.md b/README.md
index d628c21..3ad6039 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,7 @@
 # GTFS-RT: following transit vehicles in real time
 This repository contains a script that can be used to host a bokeh server.
 This bokeh server will show the live locations of busses, trams, metros, and ferrys in the Netherlands (updated every 30 seconds).
+Note that unfortunately only the data that is provided is shown, which means that some agencies are not shown.
 
 # Prerequisites
 One should have a folder called gtfs-data, containing a file called routes.txt.