Why did Gandhiji call of the Non-Cooperation Movement?

The Non-Cooperation Movement launched by Mahatma Gandhi proved quite successful. It has shaked the British Empire to its foundations for the first time since the Revolt of 1857. But in February, 1922 a group of peasants attacked a police station and set it to flames at village Chauri Chaura in Uttar Pradesh. Several policemen were burnt in this fire. Gandhiji felt angry at this violent act. So he called off the movement altogether.