1. Delhi Population, Homepage: http://www.populationu.com/in/delhi-population, Accessed on 24/03/2022
2. Gujarat Population, Homepage: http://www.populationu.com/in/gujarat-population, Accessed on 24/03/2022
3. Maharashtra Population, Homepage: https://www.census2011.co.in/census /state/maharashtra.html, Accessed on 24/03/2022
4. Rajasthan Population, Homepage: http://www.populationu.com/in/rajasthan-population, Accessed on 24/03/2022
5. Delamater, P.L., Street, E.J., Leslie, T.F., Tony Yang, Y., Jacobsen, K.H.: Complexity of the basic reproduction number (r0). Emerg. Infect. Dis. 25(1), 1 (2019)