@saurav-rox,
You can use range-area chart to fill certain region of the series with a background color. Please find the code-snippet below.
data: [
{
type: "rangeArea",
dataPoints: [
{ x: -150, y: [875,1075]},
{ x: -450, y: [875, 1375]},
{ x: -150, y: [875, 1075]},
{ x: -250, y: [875, 1175]}
]
}]
Also, please take a look at this JSFiddle for working example.

—-
Ranjitha R
Team CanvasJS