Flats are getting more common in Karachi, Lahore and Islamabad, and so is the argument. A dog in a two-bedroom apartment is either fine or it is cruelty, depending on who you ask.
The honest answer probably has less to do with square footage than with walking. A Lab that gets out twice a day is better off than a Lab on a rooftop nobody visits.
If you keep a dog in a flat — which breed, how many walks, and what do you do about the lift and the neighbours? And if you moved a dog from a house into a flat, what changed in it?