@mridhulkumar,
When I am using 3 (or less) dataPoints the chart is not plotting for the smaller values. But when I am using 4 or more dataPoints the chart is plotting correctly. (Jsfiddle Sample 1)
In this case, you can use customBreaks to add a break to remove unnecessary region manually. Please take a look at this JSFiddle for an working example on the same.
2) Not able to set viewportMaximum when using scaleBreaks. (Jsfiddle Sample 2)
Setting viewportMaximum seems to be working in the JSFiddle that you have shared. It’s setting viewportMaximum to 1000, which lies inside the scalebreak.
__
Sachin Bisht
Team CanvasJS