Hector Ruiz has made it his mission to convert old cars in Mexico City to run on electricity.

Hector Ruiz has made it his mission to convert old cars in Mexico City to run on electricity.

But with over five million vehicles in the city, he has a long way to go to have an impact on air pollution.

Reporter & Producer Natasha Pizzey

A week of coverage by BBC News examining possible solutions to the problems caused by air pollution.

But with over five million vehicles in the city, he has a long way to go to have an impact on air pollution.