In the context of proposals to the use of hydrogen-enriched CNG (H-CNG) as fuel for buses in public transport, consider the following statements: 1. The main advantage of the use of H-CNG is the elimination of carbon monoxide emissions. 2. H-CNG as fuel reduces carbon dioxide and hydrocarbon emissions. 3. Hydrogen up to one-fifth by volume can be blended with CNG as fuel for buses. 4. H-CNG makes the fuel less expensive than CNG. Which of the statements given above is/are correct?
Contents12
- A1 only
- B2 and 3 only
- C4 only
- D1, 2, 3 and 4
Show answer
Answer: (B) 2 and 3 only
The correct answer is (B) — 2 and 3 only.
H-CNG is a blend of hydrogen (about 18%) with CNG.
Statement 1 is wrong — H-CNG does NOT eliminate carbon monoxide emissions completely; it only reduces them by up to 70%.
Statement 2 is correct — H-CNG reduces both CO2 and hydrocarbon emissions compared to regular CNG.
Statement 3 is correct — hydrogen can be blended up to about one-fifth (18-20%) by volume with CNG.
Statement 4 is wrong — H-CNG is slightly more expensive than CNG (roughly Rs. 43/kg vs Rs. 42/kg).
Tip: H-CNG = CNG + 18% hydrogen. It REDUCES emissions but doesn't ELIMINATE them. Slightly costlier than CNG.
H-CNG blends about 18-20% hydrogen with CNG to reduce emissions in public transport, but does not eliminate carbon monoxide completely and costs slightly more than regular CNG.
Around 2018-19, India began pilot projects with H-CNG buses in cities like Delhi as part of cleaner fuel initiatives, making this technology relevant for UPSC.
The question tests precise understanding of emission reduction percentages versus complete elimination - a common UPSC trap between 'reduces' and 'eliminates'.
Hydrogen-Enriched CNG (H-CNG)
Environment H-CNG hydrogen-enriched CNG CNG
H-CNG: Composition, Benefits & UPSC Traps
H-CNG = CNG blended with 18-20% hydrogen by volume
Reduces CO, CO₂ and hydrocarbon emissions but does NOT eliminate them
Slightly more expensive than regular CNG (₹43/kg vs ₹42/kg)
Used in public buses as cleaner fuel alternative
What is H-CNG
H-CNG (Hydrogen-Enriched CNG) is a fuel blend where hydrogen gas is mixed with Compressed Natural Gas. This technology aims to reduce vehicular emissions while maintaining engine compatibility.
H-CNG vs Regular CNG
Parameter | Regular CNG | H-CNG |
|---|---|---|
Composition | 100% Natural Gas | 80-82% CNG + 18-20% Hydrogen |
CO Emissions | Higher | Reduced by up to 70% |
CO₂ Emissions | Higher | Lower |
Hydrocarbon Emissions | Higher | Lower |
Cost (approx.) | ₹42/kg | ₹43/kg (slightly higher) |
Engine Compatibility | Standard CNG engines | Same CNG engines (no modification needed) |
Key Technical Facts
Maximum hydrogen blending: Up to one-fifth (20%) by volume without engine modifications
Emission reduction mechanism: Hydrogen burns cleaner and enhances combustion efficiency
Engine compatibility: Works with existing CNG engines and infrastructure
Applications: Primarily tested in public buses and commercial vehicles
Question Context
This 2019 UPSC question tested understanding of H-CNG's actual capabilities vs exaggerated claims. The key trap was distinguishing between reduction and elimination of emissions.
Trap: H-CNG eliminates carbon monoxide — Wrong. It only reduces CO by 70%
Trap: H-CNG is cheaper than CNG — Wrong. It's slightly more expensive
Trap: Hydrogen can be blended in any proportion — Wrong. Maximum one-fifth (20%)
Remember: H-CNG reduces all three — CO, CO₂, and hydrocarbons
Vehicular Emission Components
Environment carbon monoxide carbon dioxide hydrocarbon emissions
Major Vehicular Pollutants: Sources & Impacts
Carbon Monoxide (CO): Toxic gas from incomplete combustion
Carbon Dioxide (CO₂): Major greenhouse gas from complete combustion
Hydrocarbons: Unburnt fuel contributing to smog formation
Nitrogen Oxides (NOₓ): High-temperature combustion products
Major Vehicular Pollutants
Pollutant | Source | Health Impact | Environmental Impact |
|---|---|---|---|
Carbon Monoxide (CO) | Incomplete combustion of fuel | Toxic - reduces oxygen in blood | Contributes to urban air pollution |
Carbon Dioxide (CO₂) | Complete combustion of carbon fuels | Not directly toxic | Major greenhouse gas |
Hydrocarbons (HC) | Unburnt fuel from engine | Some are carcinogenic | Smog formation with NOₓ |
Nitrogen Oxides (NOₓ) | High-temperature combustion | Respiratory problems | Acid rain, ozone formation |
Why These Matter for UPSC
CO vs CO₂ distinction: CO is toxic, CO₂ is greenhouse gas — different environmental concerns
Incomplete vs complete combustion: Better fuel efficiency reduces both CO and HC
Alternative fuels testing: UPSC often asks which emissions are reduced by CNG, H-CNG, ethanol blending
BS-VI norms: Focus on reducing NOₓ and particulate matter from diesel vehicles
Trap: CO and CO₂ are the same thing — Wrong. CO is toxic, CO₂ is greenhouse gas
Trap: Complete elimination vs reduction — Most alternative fuels reduce, not eliminate
Trap: All emissions equally harmful — Each has different health/environmental impacts
Alternative Fuels in Indian Transport
Environment buses public transport
India's Alternative Fuel Strategy for Transport
CNG mandate for public buses in major cities since early 2000s
Ethanol blending target of 20% (E20) by 2025-26
Electric vehicle push through FAME scheme and PLI
H-CNG trials in select cities for cleaner public transport
Alternative Fuels in India
Fuel Type | Current Status | Target/Policy | Primary Use |
|---|---|---|---|
CNG | Mandatory in Delhi NCR buses | Expanding to more cities | Public transport, commercial vehicles |
Ethanol Blended Petrol | Currently E10 (10% ethanol) | E20 by 2025-26 | Private vehicles |
Biodiesel | B7 (7% biodiesel) | B20 by 2030 | Heavy vehicles, generators |
Electric | Early adoption phase | 30% private cars by 2030 | All vehicle categories |
H-CNG | Pilot projects in select cities | Potential scaling | Public buses |
Policy Framework
National Policy on Biofuels 2018: Targets for ethanol and biodiesel blending
BS-VI emission norms: Stricter standards since April 2020 nationwide
FAME II scheme: ₹10,000 crore for electric vehicle adoption
City-specific mandates: CNG for public transport in polluted cities
India's Transport Fuel Strategy
# Clean Transport Fuels
## Immediate (2020-25)
- CNG expansion
- E10 to E20 transition
- BS-VI implementation
## Medium-term (2025-30)
- Electric vehicle scaling
- B20 biodiesel
- H-CNG deployment
## Long-term (2030+)
- Hydrogen fuel cells
- Green hydrogen
- Carbon neutralityTrap: E20 is already implemented — Wrong. Currently at E10, target is E20 by 2025-26
Trap: All cities have CNG buses — Wrong. Mandatory in NCR, expanding gradually
Trap: Biodiesel target is B10 — Wrong. Current B7, target B20 by 2030