1. The World Bank Data,
https://data.worldbank.org/indicator/EN.CO2.TRAN.ZS
2. Article on list of most-polluted cities by particulate matter concentration,
https://www.ndtv.com/gurgaon-news/india-air-pollution-gurugram-worlds-most-polluted-city-6-others-in-india-in-top-10-study-2002404
3. Article on air pollution in India,
https://en.wikipedia.org/wiki/Air_pollution_in_India
4. Article on automobiles and pollution in India,
https://community.data.gov.in/automobiles-and-pollution-in-india/
5. Article on history of the electric vehicle,
https://en.wikipedia.org/wiki/History_of_the_electric_vehicle