Automakers seek higher fuel vapour emission limit under BS VII citing E20 petrol

The central government on 14 October proposed to enforce Bharat Stage VII (BS VII) regulations starting 2029, in three phases for cars, light trucks, and heavy commercial vehicles, to ensure that vehicles made and sold in the world’s third-largest automobile market by sales emit less pollutants and greenhouse gases.

“The government should keep in mind, while setting the limit for evaporative emissions testing, that India has E20 as the base fuel, while the base fuel in Europe, used for Euro 7 norms, is E10, or E5 in some cases,” said the first of the two persons cited earlier, both speaking on condition of anonymity.

The government's push for BS VII norms comes six years after the BS6 standards took effect in 2020, aligning with a global shift towards stricter emissions regulations, including the European Union's transition from Euro 6 to Euro 7 norms from November 2026.

According to the draft BS VII notification proposed by the ministry of road transport and highways in October, the government aims to tighten the monitoring of emissions, and cover pollutants emitted by tyre wear and tear.

The government's proposed BS VII norms call for a 1.5 gram per test limit on fuel vapours emitted, meaning the vehicle must emit no more than 1.5 grams of fuel vapour during the prescribed evaporative-emissions test, according to the draft notification.

Proposal for limit

SIAM has proposed setting the limit for evaporative emissions at a minimum of 2 grams per test, citing India’s higher ethanol blending levels compared with other economies, the first person said.

To be sure, the US commonly uses an E10 blend along with flex fuel blends such as E85 and E100, and the EU also commonly uses the E10 blend in petrol.

Higher blends of ethanol in petrol can lead to a higher Reid Vapour Pressure (RVP), a measure of how easily the fuel evaporates, or turns into vapour. A draft SIAM representation on BS VII in October, reviewed by Mint, said that the RVP for India’s E20 fuel—its rate of evaporation—is higher than that of E10 fuel, therefore calling for a 2 gram vapour emission limit per test.

"BS7 standards should reflect India’s E20 fuel and driving conditions, with the choice between a 2-gram and 1.5-gram evaporative emissions limit guided by testing," said C.K. Jain, president, Grain Ethanol Manufacturers Association (Gema), an ethanol makers' lobby group.

"Higher vapour pressure can increase evaporation, but adding more ethanol does not necessarily make petrol more volatile. E20 does not automatically have higher vapour pressure than E10. Fuel composition matters, while vehicle vapour controls influence actual emissions," said Jain.

Queries emailed to SIAM, automakers Maruti Suzuki, Hyundai Motor India, Tata Motors (both passenger and commercial vehicle businesses), Toyota Kirloskar Motor; ministries of heavy industries, road transport and highways, petroleum and natural gas; and to state-run oil marketing companies Indian Oil Corporation, Hindustan Petroleum Corp, and Bharat Petroleum Corp; as well as ethanol manufacturing lobby groups Indian Sugar Manufacturers’ Association (ISMA), and All India Distillers’ Association (AIDA) on 21 October remained unanswered.

Mahindra & Mahindra declined to comment.

Rise with blends

Experts said vapour pressure rises as ethanol blends increase. "Vapour emission is bound to be more for E20 which is why this demand is being raised. Vapour increases as the blend increases due to rise in volatility, so that factor has to be incorporated in the norms for automakers to comply," said I.V. Rao, distinguished fellow, transport and urban governance, The Energy and Resources Institute (Teri), a New Delhi-based think tank.

India's decision to make petrol blended with 20% ethanol the standard fuel for all petrol vehicles from 2025 sparked consumer backlash, with motorists reporting lower mileage and engine problems.

The government has acknowledged that E20 fuel could reduce mileage by 3-5%, but maintained that vehicles had been extensively tested for the blend. In a July statement, it said ethanol-blended petrol could not be sold at a lower price because it costs more to produce, while defending the biofuels programme on the grounds that it benefits farmers, and strengthens energy security.

Mint reported earlier in December 2025 that the government was considering higher ethanol blends such as E23 and E27, as well as flex-fuel blends such as E85 and E100, especially due to the ethanol manufacturing overcapacity.

On 5 June, India also launched E85 petrol, containing 85% ethanol, at ₹20 a litre cheaper than the E20 variant. It maintained that ethanol blending was not aimed at reducing petrol prices, but at shielding consumers from volatility in global crude oil supplies and prices.

Manas is a New Delhi-based journalist with Mint, where he covers the intersection of economic policy, industry, and emerging sectors shaping India’s growth. He writes on government regulation, manufacturing, and the clean energy transition, with particular depth in areas such as electric mobility, battery ecosystems, and rare-earth supply chains. He has written on India’s efforts to build domestic capacity in electric vehicles and energy storage, as well as the broader push to reduce import dependence and strengthen supply chain resilience. His reports are not limited to capturing the headline; they also aim to explain complex policy simply.<br><br>Manas has studied law in Pune, the city where he grew up, followed by a business journalism diploma from the Asian College of Journalism in Chennai. In his almost two years of being a correspondent for Mint, Manas has reported as major wars unfolded, a general election brought surprises for both the ruling party and the Opposition, and three Union Budget announcements where India has charted its economic course for the days to come.<br><br>On vacation, Manas plays bass guitar with his friends in Space & Co, their jam-rock band. He also likes cats, and occasions of late-night snacking.

Ayaan Kartik is a Delhi-based journalist tracking the ever-growing world of automobiles and their components. With an experience of five years ranging from short-form news at Inshorts to longform journalism at Outlook Business magazine, he has dabbled into different storytelling formats. At Mint, he tries to regularly mix story styles, from longforms to crisp news stories. He has completed his graduation from Delhi University where he developed a liking for reading and writing about the world we live in today. Apart from automobiles, Ayaan likes to read up on geopolitics which has increasingly affected various sectors of the economy. Of all the promises journalism holds, he likes the fact that it allows a person to simply explain to readers about what is happening in the world. And what better sector than automobiles, which everyone since growing up has seen and felt connected to. Whether it is China's increasing grip on automobiles to growing affection for EVs in the country, Ayaan likes to connect his love for geopolitics and data to his stories as readers become more demanding on the types of stories they want.