World's Busiest Cities

Dan Snow, Anita Rani and Ade Adepitan are in Mexico City, uncovering the hidden systems and armies of people that help run it. Anita discovers how they are trying to stop this megacity from drowning in its own waste.

Dan Snow, Anita Rani and Ade Adepitan go behind the scenes to reveal the hidden systems and armies of people running Delhi – one of the biggest and busiest cities on earth.