Population of India is about 1 arab 25 corores (1,250,000,000) and every year there is an increase of total population of Australia. In another words one Australia is added to Indian population every year.
Yes. Like all countries founded on Christianity, Christmas is celebrated every year in Australia on 25 December. The main difference between Australia and most other countries is that Christmas falls in summer, and many parts of the country are very hot at that time.
Australia is Australia every day of the year, and people live there. Ice cream supplies are low though so if you are travelling from another country you may need to smuggle some in so as to satisfy your sweet-tooth.