E20 fuel ‘contaminated’ during monsoon? Petrol pump owners say some vehicles may get water-rich mixture if... — report
Petrol pump owners told The Hindu that ethanol’s hygroscopic nature leading to contamination of their E20 stock during monsoons, and in coastal areas.
Three petrol pump owners flagged a fresh challenge with E20 fuel, which contains 20 per cent ethanol and 80 per cent petrol. The fault lies in ethanol’s moisture-absorbing properties.
Petrol pump owners told The Hindu that ethanol’s hygroscopic nature (ability to attract and hold water molecules from its surrounding environment) is leading to contamination of their E20 stock during monsoons, and in coastal areas, because the existing underground storage tanks were designed for conventional petrol, not higher ethanol blends.
“The underground tanks that store fuel often have some amount of water due to ingress during rains or moisture or condensation or from the fuel tanker that brings petrol to the petrol pump," an industry veteran told The Hindu.
The expert said, “Now, when the water content in the entire E20 stock in underground tanks exceeds 0.5%, ethanol binds with water because of its hygroscopic nature or affinity for water.”
"This results in phase separation, where the water-ethanol mixture settles at the bottom of the tank, while the petrol forms a separate layer above,” they explained.
Pump owners further explained that, as the dispensing unit draws fuel from the bottom of the underground tank, some vehicles may end up receiving a water-rich mixture instead of E20.
“As a result, vehicles may not start, or break down after a certain distance. We come to know about contamination only when such customers come to us with complaints,” one of the owners told The Hindu.
They also said that the concerns were compounded in coastal areas where subsoil water is present, which can further contaminate E20 stock if the seals on underground tanks are not properly in place.
One of the petrol pump owners reportedly expressed fears that underground tanks and pipelines made of mild steel could become more susceptible to corrosion because ethanol’s tendency to absorb water could add to fuel contamination.
Some said OMCs had, however, replaced seals and washers in petrol dispensing units with neoprene rubber in preparation for E20.
Fact-check: 'Ethanol's moisture absorption is a known property'
The Federation of Automobile Dealers Associations (FADA) had earlier fact-checked the claim that E20 causes water contamination unique to ethanol-blended petrol.
It said this claim is "misleading."
"Ethanol's moisture absorption is a known property accounted for in fuel standards, storage, and vehicle design. India's E20 meets stringent BIS specifications," FADA said.
Meanwhile, the Ministry of Information and Broadcasting also said it is common knowledge that the entry of water into the fuel tank is undesirable for any fuel, whether ethanol-blended or otherwise.
"Modern vehicles are equipped with design features and safeguards to prevent water entry into fuel tanks," the ministry said.
The Ethanol Blended Petrol (EBP) Programme is one of India's key energy initiatives.
It aims to improve energy security, support farmers, and reduce environmental impact by increasing the use of domestically produced renewable fuels.
Several concerns were raised about E20 fuel after India mandated that all petrol pumps stock and supply it as the standard fuel.
The Ministry of Petroleum and Natural Gas issued a detailed clarification on the programme through a press release on 23 June 2026, addressing various concerns.
Automobile manufacturers also issued their own clarifications during a press conference held on 4 July 2026.