The Mumbai Police was on alert on Friday after its control room received a message saying bombs were placed across the city.
According to news agency ANI, the threat message was received by an unknown person.
The message stated explosives were placed at six locations in the city, following which the police launched search operations.
Meanwhile, efforts were underway to trace the person who sent the message.
On January 24, Delhi's Indira Gandhi International Airport was put on high alert, and a 'full emergency' was declared after a bomb threat call was received for a Darbhanga to Delhi flight.
It later turned out to be a hoax call.
Earlier the same month, at least eight institutions across Mumbai received emails threatening bomb blasts.
The mails also threatened to attack the Byculla Zoo.
