Our Aboriginal citizens who know Australia as Invasion Day have my sympathy. I have no strong feelings about the date, so if it would appease them, then let it be another day. Celebrating what was the establishment of a penal colony doesn't do much for me either.
Happy Australia Day to the rest of us with us having a not so bad country, even though we seem in crisis at the moment.
Happy Republic Day to India.
This is the Australian flag. Let's pull it apart, although not literally. Desecration of our flag is verboten. Top left we have the flag of Great Britain, the Union Jack, reflecting white Australia's early origins and heritage. The red vertical and horizontal cross represents the patron saint of England, St George. The diagonal red cross represents the cross of St Patrick, patron saint of Ireland. The diagonal white cross represents the cross of St Andrew, patron saint of Scotland and the patron saint of Wales St David is represented by.....well, he isn't. Later edit: Marie, aka Fun60, of London corrects me in a comment below.
The helpful information below the Australian flag explain what the stars are about. I think the seventh point to represent the territories was a later addition.