Short answers, pulled from the story.
Direct Action Day was the 16th of August 1946, declared by the All-India Muslim League as a day of general strikes and economic shutdown to demand a separate Muslim homeland. It was intended as a mass hartal in Calcutta but rapidly turned into large-scale communal violence between Hindus and Muslims.
More than 4,000 people died and around 100,000 residents were left homeless in Calcutta within 72 hours of Direct Action Day on the 16th of August 1946. The death toll in the Kesoram Cotton Mills compound in Metiabruz alone was reported to be between 7,000 and 10,000.
Suhrawardy was the Chief Minister of Bengal and the presiding speaker at the main Direct Action Day rally at the Ochterlony Monument. Two independent witnesses reported that he told the crowd he had ensured police and military would not intervene. He also spent much of the crisis in the Police Headquarters Control Room, and reports indicate he sacked Hindu policemen on the 16th of August.
Jinnah called Direct Action Day after Jawaharlal Nehru's press conference on the 10th of July 1946 effectively rejected the Cabinet Mission Plan, which had offered grouped provinces to accommodate Muslim League demands. By the 29th of July, the Muslim League had withdrawn its acceptance of the plan, and Jinnah announced the strike to press the demand for a separate Pakistan.
The Calcutta killings triggered further massacres in Noakhali, Bihar, and Punjab, making communal partition increasingly unavoidable. The violence cleared the path for Bengal's division into Hindu-dominated West Bengal and Muslim-dominated East Bengal, and the Congress leadership began accepting the proposed Partition of India in the months following the riots.
Around 500,000 Muslims left Calcutta for East Pakistan after the riots, reducing the Muslim population from 1,099,562 to 601,817. By the 1951 census, the Hindu share of Calcutta's population had risen from 73% in 1941 to 84%, while the Muslim share fell from 23% to 12%. The 1951 census also recorded that 27% of Calcutta's population consisted of East Bengali refugees.