If you are not going to project them I do not see any reason why you would not like the Ektar 100 color negative. It is cheaper to buy cheaper to develop has more latitude and is more forgiving in the huge contrasts you are definitely going to see in India and the colors are amazing.
Now if you insist on slide film I would think that Velvia 50 is way too light thirsty and Sensia 400 would prove very useful.