Mumbai Harbour or Front Bay, is a natural deep-water harbor in the southern portion of the Ulhas River estuary. The narrower, northern part of the estuary is called Thane Creek. The harbor opens to the Arabian Sea to the south. The historical island of Elephanta is one of the six islands that lie in the harbor.
Front Bay is the official name of the harbor, so named because Mumbai started as a tiny settlement facing the harbor. The waterbody behind the original settlement, forming an arc between the former Colaba island and Bombay island, up to the Malabar Hill promontory or peninsula, was similarly called Back Bay.
Front Bay is home to the Mumbai Port, which lies in the south section of the western edge of the harbor. Jawaharlal Nehru Port and Navi Mumbai lie to the east on the Konkan mainland, and the city of Mumbai lies to the west on Salsette Island. The Gateway of India with its jetty for Elephanta is the most important tourist destination, followed by the INS Vikrant maritime Museum.
Mumbai Port (MbPT) lies midway on the western shore of Mumbai Harbour. The port was the pre-eminent commercial port of India in the nineteenth and twentieth centuries. It is known as the gateway to India, and has been a primary factor in the emergence of Mumbai as the commercial capital of India.
Mangrove swamps line much of the northwestern and eastern shores of the harbour, and provide a rich habitat for wildlife, including thousands of migrating birds such as flamingoes.
Due to immense population pressures from the Mumbai metropolitan region and the extremely busy maritime trade, the Mumbai Harbour is considered to be heavily polluted. This includes reports of heavy metals flux found in the creeks adjacent to the harbour with the harbour acting as a sink for most of the pollutants.