 In March 1919 the Rowlatt Act was passed extending emergency measures of detention and incarceration in response to the perceived threat of terrorism from revolutionary nationalist organisations.This led to the infamous Jallianwala Bagh massacre in April 1919 where the British colonel Reginald Dyer ordered his troops to fire on a group of some 10,000 unarmed protesters and Baisakhi pilgrims.The Montagu-Chelmsford Reforms enacted through the Government of India Act 1919 expanded the Punjab Legislative Council and introduced the principle of dyarchy, whereby certain responsibilities such as agriculture, health, education, and local government, were transferred to elected ministers.