According to Wikipedia, a postgraduate diploma is a postgraduate qualification awarded after a university degree. It can be contrasted with a graduate diploma.
There are many universities in India that offer a postgraduate diploma in some particular stream. If you mention the subject you are pursuing your postgraduate diploma in or the subject you are interest in, I can help you with the answers to your query.

Pg Diploma obstetrics and gynecology

Hello aspirant

There are many options after pg diploma. It totally depends upon the subject you do diploma in. Please mention the subject you want to do the diploma in for more detailed answer. 

Thankyou