[25] It was also flooded with Hindu refugees from East Bengal (present-day Bangladesh) in the decades following the 1947 partition of India, transforming its landscape and shaping its politics.

A demographically diverse city, the culture of Kolkata features idiosyncrasies that include distinctively close-knit neighbourhoods (paras) and freestyle conversations (adda).

[35] The discovery and archaeological study of Chandraketugarh, 35 km (22 mi) north of Kolkata, provide evidence that the region in which the city stands has been inhabited for over two millennia.

[36][37] Kolkata or Kalikata in its earliest mentions, is described to be a village surrounded with jungle on the bank of river Ganga as a renowned port, commercial hub and a hindu pilgrimage site for Kalighat Temple.

The first mention of the Kalikata village was found in Bipradas Pipilai's Manasa Vijay (1495), where he describes how Chand Sadagar used to stop in Kalighat to worship Goddess Kali during his path to trade voyage.

His warning went unheeded, and the Nawab attacked; his capture of Fort William led to the killings of several East India company officials in the Black Hole of Calcutta.

[67] The Eastern Command of the Indian military, which is based in Fort William, played a pivotal role in the Indo-Pakistani war of 1971 and securing the surrender of Pakistan.

[72] Spread roughly meridionally along the east bank of the Hooghly River, Kolkata sits within the lower Ganges Delta of eastern India approximately 75 km (47 mi) west of the international border with Bangladesh; the city's elevation is 1.5–9 m (5–30 ft).

[77] According to the Bureau of Indian Standards, on a scale ranging from I to V in order of increasing susceptibility to earthquakes, the city lies inside seismic zone III.

[88] Rains brought by the Bay of Bengal branch of the south-west summer monsoon[89] lash Kolkata between June and September, supplying it with most of its annual rainfall of about 1,850 mm (73 in).

[96] The east–west dimension of the city is comparatively narrow, stretching from the Hooghly River in the west to roughly the Eastern Metropolitan Bypass in the east—a span of 9–10 km (5.6–6.2 mi).

Characterised by 19th-century architecture and narrow alleyways, it includes areas such as Jorasanko, Rajabazar, Maniktala, Ultadanga, Shyambazar, Shobhabazar, Bagbazar, Cossipore, Sinthee etc.

[98]: 19  As of 2003[update], the majority of households in slums were engaged in occupations belonging to the informal sector; 36.5% were involved in servicing the urban middle class (as maids, drivers, etc.)

[127] The ratio is depressed by the influx of working males from surrounding rural areas, from the rest of West Bengal; these men commonly leave their families behind.

[130][112]: 5  The unauthorised slums (devoid of basic services provided by the municipality) are occupied by squatters who started living on encroached lands—mainly along canals, railway lines and roads.

[131]: 23  Mother Teresa was awarded the Nobel Peace Prize for founding and working with the Missionaries of Charity in Kolkata—an organisation "whose primary task was to love and care for those persons nobody was prepared to look after".

[137] Among Kolkata's smaller communities are Chinese, Tamils, Nepalis, Pathans/Afghans (locally known as Kabuliwala[138]) Odias, Telugus, Gujaratis, Anglo-Indians, Armenians, Bengali Muslims, Greeks, Tibetans, Maharashtrians, Konkanis, Malayalees, Punjabis and Parsis.

[141] India's sole Chinatown is in eastern Kolkata;[139] once home to 20,000 ethnic Chinese, its population dropped to around 2,000, as of 2009[update],[139] as a result of multiple factors including repatriation and denial of Indian citizenship following the 1962 Sino-Indian War, and immigration to foreign countries for better economic opportunities.

[160] The functions of the KMC include water supply, drainage and sewerage, sanitation, solid waste management, street lighting, and building regulation.

[173] The Kolkata Municipal Corporation supplies the city with potable water that is sourced from the Hooghly River;[174] most of it is treated and purified at the Palta pumping station located in North 24 Parganas district.

[182] State-owned Bharat Sanchar Nigam Limited, or BSNL, as well as private enterprises, among them Vodafone Idea, Bharti Airtel, Reliance Jio are the leading telephone and cell phone service providers in the city.

[184][185] As of 2010[update], Kolkata has 7 percent of the total broadband internet consumers in India; BSNL, VSNL, Tata Indicom, Sify, Hathway, Airtel, and Jio are among the main vendors.

Being one of India's major city and the largest city in eastern and north-eastern India, Kolkata hosts diplomatic missions of many countries such as Australia, Bangladesh, Bhutan, Canada, People's Republic of China, France, Germany, Italy, Japan, Myanmar, Nepal, Russia, Sri Lanka, Switzerland, Thailand, United Kingdom and United States.

Notable scholars who were born, worked or studied in Kolkata include physicists Satyendra Nath Bose, Meghnad Saha,[246] and Jagadish Chandra Bose;[247] chemist Prafulla Chandra Ray;[246] statisticians Prasanta Chandra Mahalanobis and Anil Kumar Gain;[246] physician Upendranath Brahmachari;[246] educator Ashutosh Mukherjee;[248] and Nobel laureates Rabindranath Tagore,[249] C. V. Raman,[247] and Amartya Sen.[250] Kolkata houses many research institutes, including the following: Kolkata is known for its literary, artistic and revolutionary heritage; as the former capital of India, it was the birthplace of modern Indian literary and artistic thought.

[273] Coupled with social reforms led by Raja Ram Mohan Roy, Swami Vivekananda and others, this constituted a major part of the Bengal Renaissance.

[277] The Government College of Art and Craft, founded in 1864, has been the cradle as well as workplace of eminent artists including Abanindranath Tagore, Jamini Roy and Nandalal Bose.

[265]: 105 Key elements of Kolkata's cuisine include rice and a fish curry known as machher jhol,[283] which can be accompanied by desserts such as roshogolla, sandesh, and a sweet yoghurt known as mishti dohi.

[292] Among Kolkata's widely circulated Bengali-language newspapers are Anandabazar Patrika, Bartaman, Ei Samay Sangbadpatra, Sangbad Pratidin, Aajkaal, Dainik Statesman and Ganashakti.

[307] Football matches between Mohun Bagan and East Bengal, called as the Kolkata Derby, witness large audience attendance and rivalry between patrons.

[255] The Maidan, a vast field that serves as the city's largest park, hosts several minor football and cricket clubs and coaching institutes.