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)

The people of Earth also made frequent use of internal combustion engines for their cars. The Third Doctor warned UNIT that all this would unleash a great amount of carbon dioxide into, and poison, Earth's atmosphere though his warning largely fell on deaf ears. (AUDIO: Terror of the Master)