@ayanghatak,
Labels are shown at every interval of the axis. In the JSFiddle that you have shared, we observed that the interval over axisY (horizontal in case of bar chart) is getting changed when the height of the chart is updated. However, the labels of axisX (vertical in case of the bar chart) remain the same with height 200px and 400px as the interval calculated for both the heights are same.
—
Shashi Ranjan
Team CanvasJS