Impolite questions in the US would include "How much money do you make?" (sometimes people will try to make it sound more polite by saying something like, "What do you do? ... Oh, does that pay pretty well?" 

I liked your question.

There are millions of people living in India. But they all are different in their beliefs, religions and casts.

Ironically though, people come together when it comes to greeting guests or strangers or even a conversation starter by offering casual drinks or food or desserts (sweets). And now if you dare said "no, thank you". I am afraid that wouldn't help you much.

But from what I understand, you should be fine unless you patronize :P.

"Could you give me your phone number?" >< 

In the Netherlands, asking about someone's salary is not very polite. Don't be surprised if people avoid answering that question (even if they have a high salary).

Perhaps less specific to Dutch, but I think a difference between Asia and the West, is that we're much less likely to ask about future family plans. Even in a young relationship, talking about future children might be considered getting too serious too quickly.

England is similar to the Netherlands in the way Mark suggested.  

I once lived in a place in the UK once where there was high unemployment and it would have sometimes been awkward to ask : What do you do?  (Your job)  I learnt to ask "are you in work?", and even then, only at a natural point in the conversation. 

In my experience, you can almost always talk safely about food.