Internal combustion engine

Romana II noted that Aoris had invented the internal combustion engine by Era 14. They used this technology, fed with fossil fuels, to power their land vehicles. Over hundreds of years, the planet dealt with incredible pollution as a result. (AUDIO: The Paradox Planet) This was a direct result of Drang's interventions from Era 24, including stealing their clean energy source. (AUDIO: Legacy of Death)

Elsewhere, the people of Estebol were first shown the concept of the internal combustion engine by Prubert Gastridge. After its introduction, the inhabitants of the planet became more and more reliant on machines for everyday life, eventually leading to immense pollution. (PROSE: The Tomorrow Windows)

References

The Sixth Doctor said he found marsh minnows as a snack to be about as pleasant as eating an internal combustion engine. (PROSE: Mindwarp)

When conversing with Damadus about his plan to build metal roadways all across Skaro, given that the planet's technology was powered by static electricity, Barbara Wright remarked that the internal combustion engine might be a simpler alternative. (AUDIO: Return to Skaro)