Britain's Prince Harry and his wife Meghan, the Duke and Duchess of Sussex, arrived in Nigeria's capital, Abuja, on Friday to begin a three day visit of Africa's most populous nation.

It has been called an invisible epidemic. Every year, around 300,000 people in Europe die prematurely because of air pollution, according to the European Environment Agency. Those of us living in cities are particularly exposed to unsafe levels of fine particulate matter and nitrogen dioxide. The EU is trying to bring air quality closer to World Health Organization guidelines, but the political deal that has been struck includes a clause that will allow member states to delay action by up to 10 years, if specific conditions are met.

The Duchess of Sussex co-hosted a women's leadership event in Nigeria's capital city of Abuja, during which she spoke about the "eye opening and humbling" experience of discovering her own Nigerian heritage.