The sky over Seoul, for months yellow from fine dust, seems to have become blue again as the summer heat wave hits the peninsula. But the problem will continue throughout the year - and affect both North and South equally.

Both yellow dust and fine dust are a byproduct of burning fossil fuels and other industrial pollutants, and the extent to which its annual arrival to the Korean peninsula is a local, or a regional, problem is hotly debated. Much of it, granted, does originate in China, but there's certainly a connection to both Koreas' heavy reliance on coal power stations.