Can we really grow fresh greens without soil or sunlight? Right in the centre of a busy city? In the US, AeroFarms is moving food production inside - and upwards.

The "circular economy" doesn't just mean recycling. It aims to fundamentally reduce the amount of waste we produce and potentially create a zero-waste society. With the ever increasing digitisation of our daily lives, we now have more opportunities than ever to keep waste levels low.

Earlier this month, leaders from 20 major countries met at the G20 Summit in Germany to discuss the biggest challenges of our time. But in the end, no far-reaching or pioneering solutions were brought to the table. But there's certainly no shortage of ideas out there - like, for example, the concept of the circular economy.