The question, as written, simply is not worth answering for the same reason we would not accept "Is the sky blue?" as a question. Sklivvz makes it clear why that is:

Surely, for some countries the answer is yes, and for some others, not so much. E.g. pygmies, aborigines etc. have very distinct phenotypes and geographical origin. North Americans, much less

If the claim were more specific, then perhaps that would be an interesting claim. As it is, though, I don't think it's valid to question whether some geographical region have very distinct phenotypes. It is too vague to be falsifiable. The pygmies, for example, have very particular appearances, statistically-speaking. Similarly, you wouldn't confuse the average Africa from the average Japanese. However, it is harder to distinguish the average Argentinean from the average Uruguayan.

Then, you get into places like North America which have a very diverse population. For example, about 20% of Canadian residents were born outside the country. To those, you add second-generation immigrants you start to have a very ethnically diverse population. In British Columbia, for example, about a quarter of the population is a visible minority and only 18% of the population describes their ethnicity as "Canadian".

As Oddthinking notes in the comment section, Sydney is also one of such places. This is a point that the article you cite also makes:

Mike notes that Sydney boasts one of the most multicultural populations in the world and this was reflected in the faces he photographed. 35 per cent of Sydney's population were born outside of Australia and this rises to 70 per cent in downtown Sydney, Mike claims.

Facts like these make the claim very hard to investigate.

After all, the claim is only:

In many cases, however, the likeness is so strong that it's possible to guess the nationality just by taking a cursory glance at the photo.

It's not "in all cases" nor does it list specific examples. Rather, it's a rather vague comment about how some pictures gives you a good idea of which country it was taken in. And that's all that he is claiming, here: that it's possible to guess the nationality. He does not say it's obvious, that you can pick in which South Asian country the "person" is from, but that it's not misleading enough to make it impossible to guess.

That is why it's "not a real question." It's not answerable. It's too vague.

The question, as written, simply is not worth answering for the same reason we would not accept "Is the sky blue?" as a question. Sklivvz makes it clear why that is:

Surely, for some countries the answer is yes, and for some others, not so much. E.g. pygmies, aborigines etc. have very distinct phenotypes and geographical origin. North Americans, much less

If the claim were more specific, then perhaps that would be an interesting claim. As it is, though, I don't think it's valid to question whether some geographical region have very distinct phenotypes. It is too vague to be falsifiable. The pygmies, for example, have very particular appearances, statistically-speaking. Similarly, you wouldn't confuse the average Africa from the average Japanese. However, it is harder to distinguish the average Argentinean from the average Uruguayan.

Then, you get into places like North America which have a very diverse population. For example, about 20% of Canadian residents were born outside the country. To those, you add second-generation immigrants you start to have a very ethnically diverse population. In British Columbia, for example, about a quarter of the population is a visible minority and only 18% of the population describes their ethnicity as "Canadian".

As Oddthinking notes in the comment section, Sydney is also one of such places. This is a point that the article you cite also makes:

Mike notes that Sydney boasts one of the most multicultural populations in the world and this was reflected in the faces he photographed. 35 per cent of Sydney's population were born outside of Australia and this rises to 70 per cent in downtown Sydney, Mike claims.

Facts like these make the claim very hard to investigate.

After all, the claim is only:

In many cases, however, the likeness is so strong that it's possible to guess the nationality just by taking a cursory glance at the photo.

It's not "in all cases" nor does it list specific examples. Rather, it's a rather vague comment about how some pictures gives you a good idea of which country it was taken in. And that's all that he is claiming, here: that it's possible to guess the nationality. He does not say it's obvious, that you can pick in which South Asian country the "person" is from, but that it's not misleading enough to make it impossible to guess.

That is why it's "not a real question." It's not answerable. It's too vague.