Mumbai is under a sort of shutdown today due to the death of a political figure, due to which vehicles are off roads and public conveyance such as taxis have withdrawn from the roads and airports. Things are peaceful out there, but you could be stranded if you’re landing in the city today without a vehicle to pick you up. Airport authorities have organised shuttles to drop people to the nearby suburban train stations, but that is the best they could do. The following travel advisory from my airline for a flight I am supposed to take today, should give you perspective.
If you have friends or family in Mumbai, ask them to pick you up from the airport. If you’re coming over and are supposed to stay in a hotel, ask them to send you a ride. If you’re depending on a public carpool, here is a worksheet that is managing such efforts. Here is a live update of the situation. I hope things would be better by the evening.