The main reason behind the call off non-cooperation was the incident of Chauri Chaura,Uttar Pradesh where people set on fire a police station in 1922,in which 22 to 23 policemen were burnt alive. Gandhiji wanted to stop violence at any cost.
Gandhiji decided to withdraw the ‘Non-Cooperation Movement’ in February 1922 because of the following reasons :\tIn 1922, at Chauri-Chaura in Gorakhpur, a peaceful mob turned violent and clashed with the police resulting in the deaths of several policemen.\tGandhiji felt that the movement was turning violent and satyagrahis needed proper training before they were ready for a mass struggle.
In 1922 the Chauri Chaura incident where 22-23 policemen died due to violent class between people and police disheartened Gandhiji. He did not tolerate violence at any cost. Thus he called off Non-Cooperation Movement.