I agree, it is not high. The province is not a metropolitan area, province is more of a rural area. The Naval Postgraduate School is an accredited research university operated by the United States Navy and it states that the urban area (or inner city) of Kabul is made up of 615,900 residents. The Afghan government (MRRD) states that the population of Kabul City is 1,925,548. MRRD is refering to the Kabul District (metro area), which includes the small towns that are outside the urban area but still counted as part of the city. All the sources agree on the approximate 3.5 million population of Kabul province. I hope you understand all this. Thanks,