I usually carry a few hundred dollars in greenbacks with me "just in case" my ATM card doesn't work (like the machines are down). In some countries, the exchange rate is poor with cash money, and in others it is good. Also, it is sometimes difficult to use an ATM at an airport because they're controlled by some non-bank "bank" that adds a nasty exchange fee. What about India and, in particular, exchanging US dollars to Rupees at the DEL airport?

Any particular ATMs I should look for in the country, and any I should avoid?

Thanks.