On every ajax request IE11 sends request header with 'Cache-Control : no-cache'. Ajax requests not getting served from cache.

I am requesting a resource from server (.json response) with response headers as 

Cache-Control : private, max-age=21600

But still whenever data is requested, IE11 puts Pragma: no-cache in header, which makes it to get data from server rather than serving from cache.

Is it related to developer tool? If not what is the thing that's causing it? What has to be done to fix this?

Thanks