We usually devote this space to global album chart activity, with an Anglocentric bias, but this week we're concentrating our attentions on the singles that are currently making the biggest impact globally.

Of all the tracks that dropped last week, the ones making the biggest initial impact are One Direction star Niall Horan's debut single, This Town, and All We Know, the latest smash-in-waiting by the increasingly popular New York duo, The Chainsmokers.

Twenty-three-year-old Horan, from Mullingar, topped initial iTunes ...