CA - DIPLOMA or POSTGraduation Course

It is post graduation degree.

It is recognised even by the IIM Ahmedabad as equivalent degree. And many other universities have also recognised as post graduation degree.

Its a professional degree

 It is not a post graduation or diploma degree 

But it is More than that so many universities and institutions have given it the best i.e. masters level 

CA is a professional degree but more than 90 Universities in India has recognised it equllant to PG for the purpose of  Phd. The list you can obtain from www.icai.org

In legal terms it is not a post graduation degree.

- have a nice day

Thanks all, for their valuable replies