Which event was the main reason for the announcement of the Quit India Movement? What were the results of the movement?

The Quit India Movement was initiated by Mahatma Gandhi in Bombay in 1942, during WWII, after the delivery of an inspiring speech encuraging the rebellion against the British by using the phrase 'Do or Die'. Mass protests were triggered afterwards to demand the British withdrawal from India.

Everything started after the failure of the Cripps Mission, an operation undertaken by the British goverment to ensure full cooperation and support from India in the war efforts.

Although the Quit India Movement failed, due to repression, bad organization within the movement, and the lack of a clear plan of action, the British authorities realized that they could not keep India under their control in the long run, specially after the great costs derived from WWII.