Lmaoooo
There are no "surveys" or "estimates" that say Karachi is 25 million.
ALL those surveys use Pakistan's 2011 housing survey as their "source"---the housing survey stated Karachi's population to be 23 million etc but that housing survey was disregarded as ineffective, and with huge disparities by the authorities that conducted the survey.
Hence official census was done independently without relying on the housing survey of 2011. Current census is the most comprehensive demographic study available in Pakistan. And that survey revealed that Karachi's population was around 17 million (Karachi+outskirts).
So stop harping about oh Karachi's 25 million population. It never was. It was something based on a housing survey that was declared unreliable by the very body conducting the survey due to mass irregularities and malpractices found. All foreign newspapers, estimates, and reports were based off of that housing survey which was proven to be wrong.
And again, the reason Lahore has over 10m population is because Lahore city and surrounding rural areas have been marked as "Lahore Urban" area under census and that's the population of Lahore+RURAL AREAS SURROUNDING LAHORE...which are many.
Other than you idiot karachites, nobody gives a shit about Karachi. Karachi is just another city of our dear homeland. So we don't have to conspire entire census to "take away resources" from the god-sent "Karachi"