Access to life-saving medicines often relies on a complex system known as the cold-chain – the refrigerated lorries, store rooms and fridges, which keeps them at the right temperature from the factory to the patient.

However, a traditional cold chain runs on electricity- meaning that it’s often difficult to keep medicines and vaccines cold for long enough to reach the remote places and look after them when the electricity supply is intermittent.

The food we eat also relies on the cold chain to keep it cool from the farm until it reaches our plates.

We meet some of the inventors and entrepreneurs working on cooling solutions, from using enzymes from a special bacteria that make water freeze at a higher temperature, to the earthen pots keeping insulin cool in India.

Presenter: Myra Anubi

Producer/Reporter: Craig Langran

Reporters: Mayank Prakash Bhagwat, Daniel Ominde

Production Co-ordinator: Ibtisam Zein

Sound mix: Andy Mills

Executive producer: Tom Colls

Editor: Richard Vadon

Image: Alkesh and his insulin (Credit: Mangesh Sonawane, BBC)