Unfurling specifically refers to the action of unfolding a flag that has been hoisted to reveal its full design.
Hoisting refers to the action of raising a flag, banner, or other similar objects on a pole or mast.
On Independence Day, the National flag is hoisted by the Prime Minister of India at the Red Fort.
On Republic Day, the National Flag is tied as a bundle with flowers on top of the flagpole and is unfurled by the President.
The Prime Minister hoists the National Flag from Red Fort on Independence Day, which is followed by his address to the nation. On Republic Day, the President unfurls it on Kartavya Path, which is then followed by a massive parade.