Explanation: Mumbai, the capital city of Maharashtra and one of the most populous cities in India, has a unique geographical history. The city is formed by the amalgamation of seven islands: Colaba, Old Woman's Island (also known as Little Colaba), Bombay Island (the largest), Mazagaon, Parel, Worli, and Mahim. These islands were originally separated by creeks and channels, which were gradually filled in through land reclamation projects over several centuries.
The historical process of land reclamation began in the 17th century when the Portuguese and later the British started connecting the islands. The most significant reclamation efforts took place during the British colonial period, particularly in the 19th and early 20th centuries. The construction of the Backbay Reclamation Scheme in the 1920s and the subsequent development of the city's infrastructure further consolidated the islands into a single urban entity.
Understanding the geographical formation of Mumbai is crucial for comprehending its urban development and the challenges it faces today, such as flooding and infrastructure management. The city's unique history of being formed from multiple islands also influences its cultural and social dynamics, with different areas retaining distinct identities and histories.
In contrast, the other options listed do not fit the description of being formed by seven islands. Port Blair, the capital of the Andaman and Nicobar Islands, is a single island city. Kavaratti, the administrative capital of the Lakshadweep Islands, is part of a group of islands but is not specifically known for being formed by seven islands. Puducherry, a union territory in South India, is a coastal city but does not have the specific geographical feature described in the question.
Thus, the correct answer is Mumbai, as it is the only city among the options that is historically and geographically known to be formed by seven islands.