The availability of blood for transfusions saves lives after difficult births and operations. But in much of the developing world, hospitals have a blood shortage. One entrepreneur in Nigeria is working on a solution. She has developed an app that connects blood banks to hospitals, and has built a network of moped drivers to ferry blood around Lagos, the largest city in the country. World Hacks investigates whether her solution can save lives.

Also on the programme, the designers of a new “city tree” – large structures filled with moss that attempt to absorb pollution from the air.

Presenter: Mukul Devichand

Image: Moped driver in Lagos / Credit: BBC