 They had the front passenger-seat removed in order to ease entry for passengers.At the moment, the taxi population is in a transition period, with both types in use.Originally taxis were yellow with a white roof, until they were changed in the mid-1990s (allegedly because yellow was the official colour of the Partido de la Revolución Democrática, which at the time was competing for the newly created Mexican District gobernancy with the Partido Revolucionario Institucional, which is mostly identified with green colour; officially it was to identify green taxicabs as environmentally-friendly 'ecológicos', even though they were the same polluting Volkswagen Beetles).