Yellowish due to tobacco and food stain usually can be whiten back by scaling, because the stain is superficial. But if the yellowish staining is due to thinning of teeth layer ( Our teeth have 2 layers, the outer layer is whiter, and inner layer is yellowish. As time goes by, the outer layer become thinner thus the teeth become more and more yellowish ), then it whitening cant be done by scaling.

In short, scaling can be helpful for stain that is superficial. Other than that, bleaching is the other option, but the effect is not permanent.
I asked one of my friend, in Jitra, Dr Yeoh doing. Whereas in Alor Setar, Klinik Selesa in Simpang Kuala and another clinic opposite Star Parade. Im not sure how is their work, only know they providing the service

Some is just congenital and genetic. If you notice, Indian society has a much whiter teeth, one of the reason is the contrast of their skin color to teeth, making it whiter. But if you just look at the teeth itself, it also appear whiter than other races. Thinning of teeth by by daily wear and tear, or acid attack in some individual.

Good to heard that, i have a few colegue also grad from Manipal, Salem and Chennai. You going for twinning or 5 years there? Must be quite excited ya...

All the best ya...Enjoy your stay in India
From the picture, your wisdom teeth is erupting. You either bear with the pain and let it grow , or you can choose to extract it. And the extraction is going to be a little bit complicated, so the dentist might have to charge you higher.

Have fun in India, i been there for 2 years. Initially you will be reluctant to go, but it is a beautiful place. Go to Goa and Pondycherry, my favorite place 

Kedah/kelantan/terengganu is sunday to thursday 8 to 5, but thursday till 330
other state is 8 to 5, friday 1215 till 245 break