To avoid more such incidents, the city has deployed the Indian Navy, which helped shift around a thousand people from low-lying areas in the city.
The injured have been admitted to civic hospitals in Jogeshwari and Shatabdi Hospital in Kandivali.
A 45-year-old watchman also died when a wall collapsed on him late on Monday, police said.
Two persons died in Malad after they were locked up in a vehicle flooded with rain water.
Three people killed have been identified as Sobha Kacharu (60) Kareena Mohammad Chand (25), Hussain Mohammad Chand (3).
Six migrant construction workers were killed and five injured when a wall collapsed on their tin-roofed huts in Pune, a police spokesman said.
Three people died when a school wall collapsed in the city of Kalyan, 42 kilometres (26 miles) north of Mumbai. At least 50 domestic and worldwide flights were diverted and 50 other flights were canceled.
Chief Minister Devendra Fadnavis informed the state Assembly that at least 75 were injured in the monsoon havoc.
The Maharashtra state government said only emergency services would be functional in the city on Tuesday.
Meanwhile, 1,000 people were evacuated from Kranti Nagar, Kurla, due to the Mithi river overflowing, the municipal corporation said.
Suburban trains were delayed by as much as two hours because the tracks were submerged under water while some long distance trains were cancelled.
The Central railway has also suspended the movement of suburban trains, citing safety hazard.
The schedule of the cancelled examinations will be announced soon.
Fadnavis made a similar announcement in the state legislature, announcing a high-level probe into the wall collapse.
This is the second incident of a boundary wall collapse within four days.
The rains in Mumbai have not taken a break since the monsoons started on Thursday, with incessant rains overnight in many areas of the city and its suburbs. After 24 hours, rains will taper over the region and the situation may improve slightly. The rainfall recorded by the Santa Cruz observatory on that day was also 375.2 mm. Fire teams and the National Disaster Response Force were also sent to rescue people who had been crushed when a wall collapsed in Kurar village.
Mumbai rains have remained unstoppable for the last many days. "Fire Brigade and NDRF had rushed to the spot", said the BMC.
Joshi blamed "geographic phenomena" for water-logging in the city and said the BMCs monsoon preparedness was up to the mark. All three Harbour, Central and Western line services were affected, as many stations were flooded.
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