Why were people protesting in Amritsar? Why were there troops in Amritsar?

Amritsar was placed under martial law and handed over to British Brigadier General Reginald Dyer, who banned all meetings and gatherings in the city. On April 13, the day of the Sikh Baisakhi festival, tens of thousands of people came to Amritsar from surrounding villages to attend the city's traditional fairs. Thousands of these people, many unaware of Dyer's recent ban on public assemblies, convened at Jallianwala Bagh, where a nationalist demonstration was being held.