Write a short note on Jallianwala Bagh Massacre in 20 words.

Jallianwala Bagh Massacre (13 April 1919):

• Barbaric British Colonial Atrocity: On Baisakhi day, British Brigadier-General Reginald Dyer blocked the exit of Jallianwala Bagh in Amritsar and opened fire without warning on a peaceful crowd protesting the arrest of Dr. Saifuddin Kitchlew and Dr. Satyapal (Rowlatt Act).
• Impact: Killed $1,000+$ unarmed citizens; Rabindranath Tagore renounced his Knighthood.