Bharat Stage–VI (BS-VI) Emission Norms

Why is it in News?

• Delhi–NCR intensified enforcement against older, non-BS-VI private vehicles amid severe winter air pollution.
• Clarification issued that vehicles bought/registered after April 1, 2020 are BS-VI compliant, while older vehicles face:
  • Entry restrictions
  • Fines
  • Deregistration or scrappage-linked action
• Public confusion over how to identify BS-VI vehicles triggered policy and enforcement debates.

Relevance

GS III – Environment & Ecology , Science & Techology

• Air pollution and mitigation strategies
• Vehicular emissions and urban air quality
• Climate co-benefits (black carbon reduction)

What are Bharat Stage (BS) Emission Norms?

• Bharat Stage norms are India’s vehicle emission standards.
• Aim:
  • Regulate pollutants from internal combustion engines.
• Pattern:
  • Broadly aligned with European (Euro) standards.
• Progression:
  • BS-I → BS-II → BS-III → BS-IV → BS-VI
• India skipped BS-V to fast-track pollution control.

What is BS-VI?

• BS-VI implemented nationwide from 1 April 2020.
• Applies to:
  • Petrol vehicles
  • Diesel vehicles
  • Two-wheelers, cars, commercial vehicles
• Covers:
  • Vehicle engine standards
  • Fuel quality standards

How to Identify a BS-VI Vehicle?

• Registration Certificate (RC):
  • Emission norm mentioned as BS-VI.
• Fuel/engine label:
  • Often marked by manufacturer.
• VAHAN portal / mParivahan app:
  • Official verification.
• Key rule:
  • Registered on or after 1 April 2020 → BS-VI compliant
  • Vehicles registered before April 2020 → not BS-VI, even if upgraded later.

What Changed from BS-IV to BS-VI?

1. Emission Limits (Diesel Cars)

• Nitrogen Oxides (NOx):
  • Reduced by ~68%
• Particulate Matter (PM):
  • Reduced by ~82%

2. Emission Limits (Petrol Cars)

• Significant reduction in:
  • NOx
  • Hydrocarbons

3. Fuel Quality

• Sulphur content:
  • BS-IV: 50 ppm
  • BS-VI: 10 ppm
• Enables:
  • Advanced emission-control systems
  • Longer engine life
  • Cleaner exhaust

4. Advanced Technologies

• Diesel vehicles:
  • Diesel Particulate Filter (DPF)
  • Selective Catalytic Reduction (SCR)
• Petrol vehicles:
  • Improved catalytic converters
• Mandatory On-Board Diagnostics (OBD).

Why Are Older Vehicles More Polluting?

• Lack advanced emission-control systems.
• Higher emissions of:
  • NOx
  • PM2.5 and PM10
• Diesel vehicles particularly harmful:
  • Fine particulates penetrate lungs and bloodstream.
• Urban impact:
  • Vehicles contribute disproportionately to winter smog due to:
    • Temperature inversion
    • Low wind speeds

Why Does Delhi–NCR Enforce Stricter Rules?

• Delhi introduced tighter emission norms earlier than the rest of India.
• Context:
  • Extremely high vehicular density
  • Unfavourable meteorology
• Judicial backing:
  • Supreme Court–mandated measures
  • GRAP (Graded Response Action Plan)
• Data cited by authorities:
  • ~37% of vehicles in NCR are highly polluting, mostly older models.

Health & Environmental Rationale

Health Impact

• Vehicular pollution linked to:
  • Asthma
  • Chronic bronchitis
  • Cardiovascular diseases
• PM2.5 classified as carcinogenic by WHO.

Environmental Impact

• Formation of:
  • Urban smog
  • Ground-level ozone
• Long-term climate co-benefits:
  • Lower black carbon emissions.

Economic & Social Implications

Positive

• Cleaner air
• Reduced public health expenditure
• Push towards:
  • Cleaner fuels
  • Electric vehicles

Challenges

• Costlier BS-VI vehicles.
• Maintenance issues:
  • DPF clogging in low-speed urban driving.
• Impact on lower-income vehicle owners.

Policy Linkages

• National Clean Air Programme (NCAP)
• Vehicle Scrappage Policy
• FAME scheme (EV push)
• GRAP for Delhi–NCR

Critical Issues & Concerns

• Enforcement-heavy approach:
  • Risks social backlash.
• Air pollution is multi-source:
  • Construction dust
  • Biomass burning
  • Industrial emissions
• BS-VI alone cannot solve urban air pollution.

Way Forward

• Combine BS-VI enforcement with:
  • Public transport expansion
  • EV adoption
  • Urban planning reforms
• Scrappage incentives over punitive bans.
• Fuel quality monitoring nationwide.
• Address non-vehicular pollution sources.

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