The census enumeration drive in the city will be extended by a month to July 15.
Admitting that 10 per cent of the city's population was yet to be enumerated, the municipal corporation had sought the Central government's approval to extend the June 15-deadline.
"We'll need an additional four weeks to complete the enumeration process of the entire city," said Additional Municipal Commissioner Manisha Mhaiskar, who is also additional principal census officer.
The Centre agreed to extend the deadline until July 15.
On June 3, Hindustan Times had reported how the enumerators had found 10 per cent of the houses locked, and hence failed to enumerate them.
"We found that 10 per cent of the houses were locked every time our enumerators paid a visit. Reaching out to this 10 per cent was very difficult. Also, our past experience with the pulse polio campaign shows that 5 to 7 per cent of the houses are always locked."
The BMC has decided to take a two-pronged approach include those left out in the population counting.
"We have launched ward helplines where the citizens, who haven't been enumerated, can call and register. Our enumerators too will try to contact those who haven't been enumerated," said Mhaiskar.
The BMC has also decided to tone down the scale of its operations. It won't employ all of the 31,797 enumerators for counting the remaining 10 per cent population.
"Now we will be employing officials from our Health department itself to enumerate for the next four weeks."
The Census, the 15th to be carried out in the country and the seventh in Independent India, will be carried out in phases.
The first phase began on May 1 with 31,797 enumerators surveying more than 43 lakh homes in Mumbai.