The Western Railway suburban services were stopped completely due to flooding on tracks at most places in the city and surrounding and many outstation trains were stuck at various locations.
There was waist-deep water in some parts with water entering ground floor homes or buildings in many low-lying areas.
The downpour, which started after midnight, continued virtually non-stop and led to waterlogging or flooding in most parts of the city and the Mumbai Metropolitan Region (MMR).
The BrihanMumbai Municipal Corporation said its rain guages recorded over a staggering 157mm (15.7 cms) in the south Mumbai, 14 cms in eastern suburbs and 13 cms in western suburbs.
The Maharashtra government, BMC,A and the coastal Konkan districts of Ratnagiri, Raigad, Palghar, Thane and Raigad are on high alert with the Disaster Management Units in readiness for any eventuality.
Tourism Minister Aaditya Thackeray, who is Mumbai Suburban Guardian Minister, said the situation is being closely monitored.
"As of 3 a.m., rainfall measured by IMD. Some places have crossed 200 mm now. A Mumbai has faced an extremely intense system of precipitation accompanied by thundering. The BMC pumps are operational and officers are on ground," Thackeray said.
According to KS Hosalikar, Head SID, Climate & Research Services, Pune, said: "Extremely Heavy rainfall realized so far and severe floodings observed due to very very intense spell in a very short time."
The IMD has forecast heavy to very heavy rainfall in Mumbai during the day.