The civic health authorities have so far declared three sprawling fishing colonies in Mumbai as 'containment zones' and imposed lockdown by barring all entry-exit points there, official sources said.
They are: Versova fishing colony, Mahim fishermen colony, both isolated this week, and earlier last month, it was the Worli Koliwada.
The drastic move was implemented after more than a dozen fishermen have been detected COVID-19 positive in both Versova and Mahim fishermen colonies.
"All fishermen are voluntarily cooperating with the authorities, they have already stopped all fishing activities since the lockdown started and now they are remaining indoors," said Vijay Bhandarkar, Chairman of Bhai Bhandarkar Maharashtra Machhimar Vishwastnidhi Trust.
The three fishing colonies - all on the west coast of Mumbai - account for more than 65,000 fisherfolk, besides a non-fishing population of another 50,000, said Bhandarkar.
Earlier, the Worli Koliwada has been under lockdown since March 30 after 4 positive cases were found, but the situation is under improvement there.
Bhandarkar said that in Versova, the authorities have also shut the ferry service linking it with Madh Jetty across the Versova Creek as a precaution.
Besides Worli, Andheri, Mahim, the other prominent fishing colonies in the city are Cuffe Parade, Khar-Danda, Marve, Madh, Manori and Gorai.