Welcome Vikaas.
I hope you are able to propose some aesthetic use for the areas under the flyover.
The best use for a city like Mumbai would be greening/landscaping, fountains etc.
And no commercial or kiosks as it will add to the chaos on the traffic on the roads.
Hyderabad has beautiful fountains and landscaped greens under the tiny flyovers it has.
I think the Mayor or the commissioner of the BMC had just visited Hyderabad to learn how our civic authorities are making the 'Clean and Green' slogan a reality out there.
Well BKM, originally ( I mean historically) the name was Mumbai( after the goddess/diety Mumba Devi). The Britishers as usual called it Bombay as it may have been easier to pronounce. They did that to many places.
Now the politically correct name is Mumbai. It will take time for the Indians( Including me ;-) ) to get used to the old name. As I still call it Bombay.