Adding shade to specific parts of contour plots

I am trying to plot something like this

This is just an example plot of what I am trying to do. The closest I have gotten with regards to shading is something like this

using Contourf plots.

Any help would be really appreciated.

[KSSV]

Have a look on colormap...use contourf and change the colormap to gray.

[Asif Anwar Baig Mirza]

I did do that too, but the results are just the same. The region where it's white, I still have lines which I want everyone to observe however, the shaded region is the more important one. Here is a proof of trying Gray.

[KSSV]

Your whie region has values between 10 and 50...try replacing those values with NaN..so that you can get white color. Or, get the contour lines and labels, use your required color using fill, patch.

[Asif Anwar Baig Mirza]

I did try doing this too. I cannont fine control the region of Nan hence I end up with weird squares looking shaded region. Thank you for throwing ideas for me.

[KSSV]

Atatch your data.... the other option is..get each line out from contour and use patch.

When you repalce with NaN's try increasing the size of matrix..so you can make the resolution fine.