  We present colour-magnitude diagrams of open clusters, located in the range
$112^\circ < l < 252^\circ$, manifesting stellar populations in the background
of clusters. Some of the populations are found to be located beyond the Perseus
arm and may be the part of Norma-Cygnus (outer) arm. The outer arm seems to be
continued from $l\sim120^\circ$ to $l\sim235^\circ$. The background populations
follow the downward warp of the Galactic plane around $l\sim240^\circ$.
