Funny, you don't look Afghan
Those are some white-ass kids. Not "white" as in maybe-there's-some-white-on-his-pappy's-side "white". Those are some white-ass kids. Not just Caucasoid or Caucasian, but white.
VOICE OF DOUBT
Oh, come on, Jeet. Matthew Leeming didn't take those photos in Afghanistan. He probably just rounded up a bunch of the neighborhood kids, slapped some kurta pyjama on them and made them pose in a quarry, "Doctor Who"-style.
Laban Tall followed up on his comment about the Afghan descendants of Alexander the Great's armies with a link to Matthew Leeming's Spectator-sponsored Alexander in Afghanistan Expedition. Leeming, to his credit, fully acknowledges the possibility that "European" features among Afghans may not necessarily be the legacy of Alexander's armies, though the only alternative hypothesis he seriously entertains is descent from an indigenous Indo-European population. Leeming notes that
[Alexander] founded between eight and twelve [cities] in Afghanistan [that] formed the backbone of one of the least known civilisations in the ancient world: the Greek kingdom of Bactria that flourished between 300 and 148 BC....until it fell to nomad invaders from Central Asia.C. 176-160 BCE, the Xiongnu1 vanquished the Yuezhi, expelling them from Gansu. The Yuezhi fled west, settling in the valley of the Ili River near the Ysyk Kul, displacing the Scythians there in turn.
The Huns were also causing trouble for the Han Emperor Wudi who, seeking allies against them, naturally thought of the Yuezhi. In 139 BCE, a diplomatic delegation led by courtier Zhang Qian set forth to establish an alliance with the Yuezhi against the Huns.
Unfortunately for Zhang Qian, before he could reach the Yuezhi, they were attacked by the Wusun, then a Hun tributary, who ejected the Yuezhi from their new home. The Yuezhi fled further west along the Fergana Valley through the realm of Dayuan into the realm of Kangju crossing southwards over the Oxus River.
By the time Zhang Qian reached the Yuezhi in 129 BCE, they had settled in quite comfortably and lost all interest in avenging themselves on the Xiongnu.2 Also called "Tocharians," the Yuezhi spoke an Indo-European language. The land the Yuezhi had just conquered for their own was called "Bactria" by its former rulers who, by coincidence, also had Indo-European origins, the legacy of a Greco-Macedonian conquest of the region almost two centuries before.
So there is a third possibility that Leeming does not consider: an Indo-European invasion subsequent to Alexander's conquest. Or, for that matter, a fourth, more recent one: the loneliness of Western colonials on those cold, cold mountain nights.
1Identified with the Huns though the association has not been conclusively proven
2Readers who recognize the name Zhang Qian will know that, as tortuous as the course of his mission is depicted here, his entire ordeal was actually much, much worse.