Vihar Lake is located near Vihar village on the Mithi River within the precincts of the Borivali National Park, also called the Sanjay Gandhi National Park, in North Mumbai. When built in 1860 (construction started in 1856), it was considered as the largest lake in Mumbai in the Salsette group of islands. It is hemmed between the Tulsi Lake and the Powai Lake(shown in map). It partly meets the drinking water needs of the South Mumbai region. It supplies only 3 % of the Mumbai city’s water requirement, after filtration at Bhandup where the large water filtration plant is located. .

With the few thousand wells feeding the population of Mumbai tending to go dry during summer, the acute shortage of water resulted in protests by the local residents in June 1845. A two man committee, appointed by the British rulers of the time, to examine the grievances of the agitators concurred with water shortage problem and stressed the urgent need to solve the water supply problem of Mumbai.

The Committee appointed by the government located suitable sites to construct dams and create reservoirs to store the monsoon flows of the Mithi river catchment, which resulted in presently existing Vihar Lake, Tulsi Lake and the Powai Lake. Vihar reservoir was the first piped water supply scheme of Mumbai.

Sanjay Gandhi (Hindi: संजय गाँधी ) (14 December 1946 – 23 June 1980) was an Indian politician. The younger son of Prime Minister Indira Gandhi and Feroze Gandhi, he was a member of the Nehru-Gandhi family. During his lifetime he was widely expected to succeed his mother as head of the Indian National Congress, but following his early death in a plane crash his older brother Rajiv became their mother's heir, and succeeded her as Prime Minister of India after her death. Sanjay's widow Maneka Gandhi and son Varun Gandhi are also politicians.

Sanjay, along with his elder brother Rajiv Gandhi, studied Grades 1 to 6 at the Welham Boys' School. Rajiv studied Grades 7 to 12 at The Doon School in Dehra Dun. Sanjay studied Grades 7 and half of Grade 8 at the Doon School and the remainder of Grade 8 through Grade 11 at St. Columba's School, Delhi. Sanjay never attended college, but took up an apprenticeship with Rolls-Royce in Crewe, England. He was very interested in sports cars, and also obtained a pilot's license. While he was building a career as an airline pilot independent of politics, Sanjay still chose to remain close to his mother.