Experts Urge BS7 Reform: India Must Control Fuel Vapor Loss

India is preparing for BS7 emission standards, but evaporative emission remains largely unaddressed. Experts warn that fuel vapors, not from exhausts but from fuel tanks and lines, are escaping — especially during refueling or hot weather.

“Evaporative emissions are volatile organic compounds which are one of the major contributors to the formation of particulate matter and ozone, creating smog and haze,” Dr Terry Lathem, Manager-Government Relations, Ingevity Inc, during a webinar hosted by Autocar Professional and ECMA.

These vapors, often invisible, include hazardous compounds like benzene. During hot months, India’s petrol vehicles can emit 40–60 grams of vapor daily, even while parked. This is worse when E20 fuel is used, since ethanol increases vapor pressure.

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“Petrol is a volatile liquid and it evaporates into the air quickly. Ethanol when mixed with petrol increases the fuel’s vapor pressure, leading to more evaporation. If those vapors aren’t captured, they’re released into the air, harming human health, and wasting fuel,” Lathem explained.

Though diesel vehicles emit less due to lower vapor pressure, many light commercial vehicles now run on petrol blends. For fleet owners, that means more fuel evaporating, not burning.

“What’s happening right now is like letting money evaporate into the air. Every refueling event without proper control can release up to 100 milliliters of petrol, that’s nearly ₹10 lost, every single time,” Lathem pointed out.

ORVR Systems: Used Globally, Ignored in India

Globally, vehicles include Onboard Refueling Vapor Recovery (ORVR) systems. These use carbon canisters to trap vapors and feed them into the engine. Countries like the US, Brazil, and China use ORVR to recover up to 98% of fuel vapors.

In India, however, ORVR systems are rare. Instead, vapor control is often left to fuel stations, where systems are inconsistent.

“Stage II vapor recovery at stations was tried in Europe and US, but it’s expensive and unreliable in real-world use. The US has mandated ORVR at the vehicle level. It works better, costs less, and needs no maintenance,” said Lathem.

Indian Testing Standards Don't Reflect Reality

India mirrors Euro 6D evaporative norms, which test vehicles at 35°C max. But Indian cities often cross 40°C, making those test conditions irrelevant.

“Simple changes to Bharat regulations can lead to the adoption of improved control technology. Larger canister systems are needed to prevent excess diurnal evaporative emissions during India conditions and improve refueling controls,” he added.

The Fix: Simple, Cheap, Effective

Experts say India can adopt larger canisters, already used in US-spec vehicles, without major redesigns. Each system costs under ₹3,000 and lasts the vehicle’s lifetime.

“It’s rare in the emissions world to find a control technology that saves money while cutting pollution,” Lathem said.  “But this is one of them.”

Conclusion: Commercial Vehicles and the Cost of Delay

With millions of petrol-powered vehicles; including vans, pickups, and LCVs on Indian roads, ignoring evaporative emissions could cost both fuel and public health. As India finalizes BS7 regulations, experts urge policymakers to mandate ORVR or at least update test profiles.

“Evaporative fuel vapors contain hazardous air pollutants, such as benzene, which are harmful to health and can cause cancer,” warned Lathem.

If India acts now, it can save fuel, cut smog, and help commercial vehicle operators lower losses at the pump, without costly tech or major redesigns.

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