There are doctors who return back to India after completing their residency or residency + fellowship in US. Most of them work in the corporate hospitals or other private setups. It takes time to adapt to the problems of Indian patient population as the epidemiology of diseases is quite different in India and US. You will think of different set of differentials while dealing with the same set of symptoms in India. A common example which is given is of chronic cough. You will think of tuberculosis first rather than sarcoidosis or histoplasmosis when you are practicing in India.
Moreover, you will be paid almost equal to the doctors who have completed their medical education in India and have been dealing only with Indian patients all their life. The main purpose of many doctors who go for residency in US is to earn money. If you come back after doing residency, this purpose gets wasted.
So if you are very sure that you will return back to India, its better to do PG here and you can choose speciality of your choice as well ; especially if you are interested in surgical fields. Otherwise you have to stick with one of these in US – Internal Medicine, Pediatrics, Psychiatry or Family Medicine. Most of the IMGs get into residency in one of these.