I am traveling with my elderly parents, sister and her son. He is 19 years old. We are traveling to Rome, from Sydney return on Air India. We have a 12 hour stopover in Delhi, so I have booked a hotel without thinking about the transit visa. I have a New Zealand passport, my parents have both New Zealand and Australian Passports and I'm not sure what my sister's or nephew's passports are.
I would like to know if we need transit visas and how to get them before we depart Australia.