my friend has just said that her cousin did MBBS in china and he is trying to join here to work as a doctor and he is attempting that entrance exam and it is really sooo difficult to attempt

@ bhanu 
Yes , you are right , if u have studied MBBS from some abroad country then for working as a govt doctor , u have to get PG in india only , 
and for that u have to write PG entrance exams , and obviously that is difficult , 
AND IF YOU ARE REFERRING TO TO PG (POST GRADUATE IN MEDICINE ) FROM AIIMS THEN I COULD SAY , ITS VERY VERY DIFFICULT . 
BEACUSE IN AIIMS , GETTING PG REQUIRES PROPER AMOUNT OF HARDWORK , AND PATIENCE . 
and u also have to adopt some strategy to attempt the paper their . 
BUT IT DOESNOT MATTER FROM WHERE U DID THE MBBS , IF U DID THAT FROM INDIA ALSO , THEN U HAVE TO AGAIN ATTEND THAT ENTRANCES TO GET PG . 
but in private , i donot think there are any such pg examination , if now MCI employed for private then that must be easy , but govt one is difficult .. 
HOPE IT CLEARS YOUR DOUBT 
ALL THE BEST ..