They built two arterial roads (Sydenham Road, now known as Mohammad Ali Road after its ghettoisation by Muslims) which, along with Princess Street (mostly Christian and Parsi), were designed to let in sea water and light and air into the dark, dank quarters that existed along them at the time. Sadly, these streets have gone back to being dank, damp and densely populated.
Although Mohammad Ali Road is now being redeveloped by a trust set up under government sanction by the Syedna, the spiritual head of the Bohra community, according to Abuzar Zakir, an administrator at the Saifee Hospital, which was also beautifully rebuilt by the Sydena and today is an outstanding landmark in South Mumbai, it has not been easy as the residents seem to be resisting development and modernisation as fiercely as native residents of chawls and community settlements had done during the British era.
However, both the government and the trust are determined to give the area a complete makeover and it is with the same determination and spirit that the government must now descend on Dharavi, the remaining chawls on the textile mill lands and other slums of Mumbai to give the people a cleaner environment to live in.
Source: https://www.nationalheraldindia.com/opinion/the-british-rebuilt-bombay-after-the-plague-of-1896-mumbai-needs-to-be-rebuilt-now