Hello @kartik,
If you want to manually add support to your site, you can just add the following to your web.config in the system.webServer section:
<staticContent>
<mimeMap fileExtension=".json" mimeType="application/json" />
</staticContent>
This will add a "local" configuration under IIS. This does not work in IIS6, but does work in IIS7 and newer.
Hope it is helpfull!!
Thank you!!