Bharat you will be able to find more local responses on
http://www.indianrealestateforum.com/ If you have never been to Delhi, it's not going to be easy at all. 6 months of real hot summer. Traffic woes. If you manage to live in a flat, you could be safe. Living in a house is extremely unsafe. There are lots of oppurtunity in Gurgaon and Noida with some great flats/societies. But nothing close to Australia. I have lived in Sydney for years. If you focus on your job and manage to make some friends, it is going to be fine. If you want to do travel around, it ain't gonna be easy. Ask yourself why you want to come here for.
More Money?
Peace of Mind?
Well, if you have a decent job in Aus and happy with it, it will be better if yu stay back.
I know every NRI loves India. But then, then love it because they don't live here. Good for a holiday. If you want to settle here, you will have to make many compromises. Are your ready for that for the sake of money?
Enjoy