Concerns over possible chloride contamination in India’s E20 ethanol-blended petrol have intensified in recent weeks after the Society of Indian Automobile Manufacturers (SIAM) raised alarms about rising failures in vehicle components. The industry body initially reported that members were seeing increased replacements of fuel injectors, fuel pumps, exhaust gas recirculation valves and other parts that come into direct contact with fuel or engine emissions. Investigations into the failed parts, SIAM said, pointed to corrosion or wear linked to high chloride levels traced to the fuel itself.
In its letter to the Petroleum Ministry, SIAM cited fuel samples from vehicle tanks showing chloride concentrations as high as 500 parts per million and samples from retail outlets reaching up to 350 ppm. It also flagged elevated moisture levels that could cause phase separation, potentially immobilising vehicles soon after refuelling. The body noted that such issues had become more noticeable after the nationwide rollout of E20.
Within days SIAM withdrew the letter, stating that some of the numbers required further authentication through broader data collection and consultation with manufacturers. The withdrawal has not ended the debate. Consumer complaints about reduced mileage and component problems continue to circulate, particularly among owners of older vehicles not originally designed for higher ethanol blends.
Public sector oil marketing companies responded with a joint statement rejecting the contamination claims. Intensive testing across the supply chain including more than 100 petrol samples from refineries, ethanol from 80 distilleries, samples from terminals and over 160 samples from retail outlets, showed chloride levels consistently in the range of 0–3 ppm, far below the figures that had been reported. Only a few isolated cases of elevated chloride were detected, after which supplies at the affected outlets were suspended pending corrective action. The companies also rejected claims of widespread excess moisture.
The government has maintained that E20 does not cause abnormal engine wear or reduce vehicle life when quality standards are met. It has cited manufacturer service data, including one leading carmaker that serviced 2.84 crore vehicles in FY 2025-26 (including many older non-E20-certified models) without reporting E20-linked corrosion or abnormal wear. Officials have described much of the public concern as a misinformation campaign and noted that only two cases of chloride contamination were found in earlier routine sampling of around 2,000 tests.
Chloride ions are known to attack the protective oxide layer on metals used in fuel systems, leading to pitting and eventual component failure. Ethanol’s affinity for water also raises the risk of phase separation if moisture levels rise. These scientific points explain why the issue has drawn attention even as official testing has so far failed to validate claims of widespread high contamination.
The controversy has left motorists in a position of uncertainty. While the government and oil companies insist the fuel meets specifications and large-scale field data show no systemic damage, the initial industry warning and subsequent withdrawal have kept questions alive about quality monitoring at the retail level and the long-term effects on vehicles, especially older ones. Further independent verification and clearer communication on chloride limits in fuel standards will be needed to settle the matter.
