Which parts in old cars can get damaged with the use of ethanol-blended petrol?

ARAI's Journal of Mobility Technology (2021) found that ethanol-blended petrol in older vehicles, including ones that are BS-III compliant, can damage fuel-system components, NDTV reported. E20 can cause greater hardening, loss of strength and flexibility and swelling in some older vehicles' parts. The parts that may get damaged include seals, hoses, gaskets, O-rings, pipes and fuel hoses.