Anti-Muslim riots break out in Calcutta, in response to anti-Hindu riots in East Pakistan. About one hundred people are killed.

Since the partition of India in 1947, there have been several instances of religious violence against Muslims. These incidents often take the form of violent attacks on Muslims by Hindutva mobs, forming a pattern of sporadic sectarian violence between Hindu and Muslim communities. From 1954 to 1982, nearly 7,000 incidents occurred, resulting in the deaths of over 10,000 people

Kolkata, also known as Calcutta, is the capital and largest city of the Indian state of West Bengal. It lies on the eastern bank of the Hooghly River, 80 km (50 mi) west of the border with Bangladesh. It is the primary financial and commercial centre of eastern and northeastern India. Kolkata is the seventh most populous city in India with an estimated city proper population of 4.5 million (0.45 crore) while its metropolitan region Kolkata Metropolitan Area is the third most populous metropolitan region of India with a metro population of over 15 million. Kolkata is regarded by many sources as the cultural capital of India and a historically and culturally significant city in the historic region of Bengal.

The 1964 East Pakistan riots refer to the massacre and ethnic cleansing of Bengali Hindus from East Pakistan in the wake of an alleged theft of what was believed to be the Prophet's hair from the Hazratbal shrine in Jammu and Kashmir in India. The salient feature of the pogroms was its urban nature and selective targeting of Bengali Hindu owned industries and merchant establishments in the capital city of Dhaka. This resulted in unending waves of Bengali Hindu refugees in neighbouring West Bengal. The refugee rehabilitation became a national problem in India, and hundreds of refugees were resettled in Dandakaranya region of Odisha & Madhya Pradesh ..

East Pakistan was the eastern province of Pakistan between 1956 and 1971, restructured and renamed from the province of East Bengal and covering the territory of the modern country of Bangladesh. Its land borders were with India and Burma, with a coastline on the Bay of Bengal. East Pakistanis were popularly known as "Pakistani Bengalis"; to distinguish this region from India's state West Bengal, East Pakistan was known as "Pakistani Bengal". In 1971, East Pakistan became the newly independent state Bangladesh, which means "country of Bengal" or "country of Bengalis" in the Bengali language.