Rodney Wear
Rodney Wear voted up Baha Hill's answer

Formal dinner require finest quality national dress. In different states the dress code is different. Man can be dress in classic suit, usually it is. Or wear a suit with Indian element, like a high neck or some embroidery
Types of traditional man dress in India are Sherwani, Dhoti Sherwani, Nehru jackets, Salwars, Kurta Pyjama, … Read more

Rodney Wear
Rodney Wear voted up Anonymous' answer
If you are a male then I suggest to wear traditional Indian dress like Kurta and Pajama with traditional cap. If you are female then my recommendation is to wear traditional Sari. If you have fair complexion then my suggestion is to use black sari with skilled work on it.
I suggested these dresses … Read more