structural:expansion
Civic administration

Kolkata is administered by several government agencies. The Kolkata Municipal Corporation, or KMC, oversees and manages the civic infrastructure of the city's 16 boroughs, which together encompass 144 wards. Each ward elects a councillor to the KMC. Each borough has a committee of councillors, each of whom is elected to represent a ward. By means of the borough committees, the corporation undertakes urban planning and maintains roads, government-aided schools, hospitals, and municipal markets. As Kolkata's apex body, the corporation discharges its functions through the mayor-in-council, which comprises a mayor, a deputy mayor, and ten other elected members of the KMC. The functions of the KMC include water supply, drainage and sewerage, sanitation, solid waste management, street lighting, and building regulation.

Kolkata's administrative agencies have areas of jurisdiction that do not coincide. Listed in ascending order by area, they are: Kolkata district; the Kolkata Police area and the Kolkata Municipal Corporation area, or "Kolkata city"; and the Kolkata metropolitan area, which is the city's urban agglomeration. The agency overseeing the latter, the Kolkata Metropolitan Development Authority, is responsible for the statutory planning and development of greater Kolkata. The Kolkata Municipal Corporation was ranked first out of 21 cities for best governance and administrative practices in India in 2014. It scored 4.0 on 10 compared to the national average of 3.3.

The Kolkata Port Trust, an agency of the central government, manages the city's river port. As of 2023, the All India Trinamool Congress controls the KMC; the mayor is Firhad Hakim, while the deputy mayor is Atin Ghosh. The city has an apolitical titular post, that of the Sheriff of Kolkata, which presides over various city-related functions and conferences.

As the seat of the Government of West Bengal, Kolkata is home to not only the offices of the local governing agencies, but also the West Bengal Legislative Assembly; the state secretariat, which is housed in the Writers' Building; and the Calcutta High Court. Most government establishments and institutions are housed in the centre of the city in B. B. D. Bagh (formerly known as Dalhousie Square). The Calcutta High Court is the oldest High Court in India. It was preceded by the Supreme Court of Judicature at Fort William which was established in 1774. The Calcutta High Court has jurisdiction over the state of West Bengal and the Union Territory of the Andaman and Nicobar Islands. Kolkata has lower courts: the Court of Small Causes and the City Civil Court decide civil matters; the Sessions Court rules in criminal cases. The Kolkata Police, headed by a police commissioner, is overseen by the West Bengal Ministry of Home Affairs. The Kolkata district elects two representatives to India's lower house, the Lok Sabha, and 11 representatives to the state legislative assembly. The Kolkata police district registered 15,510 Indian Penal Code cases in 2010, the 8th-highest total in the country. In 2010, the crime rate was 117.3 per 100,000, below the national rate of 187.6; it was the lowest rate among India's largest cities.