SEOUL – A severe heat wave has changed the currency of cool in Seoul’s affluent district of Gangnam: access to air conditioning now defines the line between the haves and the have-nots.

The ritzy neighborhood was made globally famous by K-pop star Psy’s 2012 hit single “Gangnam Style” — lauding the lifestyles of its ultra-rich residents.

But under million-dollar luxury apartments chilled by whirling air conditioners, tenants in one of Seoul’s last shantytowns suffer headaches in the savage heat.