What are Bharat Stage Emission Standards?

•  Bharat Stage (BS) emission standards are regulations established by the Indian government to control the output of air pollutants from internal combustion engines in vehicles.
•  The first standards were introduced in 1991, with subsequent updates leading to the current BS-VI standard, which came into effect on April 1, 2020. India has progressively aligned its standards with European norms, skipping BS-V altogether due to increasing pollution levels.

What is the difference between BS-IV and BS-VI norms?

• • Sulphur Content: BS-VI fuel has a significantly lower sulphur content (10 ppm) compared to BS-IV fuel (50 ppm), resulting in reduced harmful emissions.
• Nitrogen Oxide (NOx) Emissions:

• • Diesel Vehicles: NOx emissions are limited to 80 mg/km under BS-VI, down from 250 mg/km under BS-IV.
  • Petrol Vehicles: NOx emissions are reduced from 80 mg/km in BS-IV to 60 mg/km in BS-VI.
• Particulate Matter (PM): The permissible PM emissions for diesel vehicles have been reduced from 25 mg/km under BS-IV to 4.5 mg/km under BS-VI. Petrol vehicles are also subject to a new limit of 4.5 mg/km for PM.
• Emission Control Technologies: BS-VI introduces advanced technologies such as Selective Catalytic Reduction (SCR) and Diesel Particulate Filters (DPF), which were not part of the BS-IV standards. Additionally, Real Driving Emissions (RDE) testing is implemented to monitor emissions during actual driving conditions.

A study by the Centre for Science and Environment reveals that:

• Vehicular emissions are the largest contributor to Delhi’s air pollution, accounting for 51.5% of the city’s pollution;
• Neighbouring districts add 34.97 %,
• Farm fires contribute 8.19%, and
• Dust particles make up 3.7 % of the total air pollution in the city.

What is the AQI Crisis in North India and What is the role of Climatic Conditions?

• Northern India, particularly Delhi, is currently facing a severe air quality crisis, characterized by record-breaking Air Quality Index (AQI) levels. The AQI in many areas has exceeded 500, categorizing it as “severe-plus,” which poses significant health risks and limits visibility due to thick smog.
  • This year, despite a relatively pollution-free October and early November, the second week of November brought a sudden spike in toxic particulate matter, primarily PM2.5.
• Weather Patterns: Inversions and stagnant air conditions have contributed to the accumulation of pollutants. The presence of a thick pollution blanket at around 500 meters above ground level has been linked to adverse local impacts when combined with regional emissions from stubble burning and other sources.
• External Pollution Sources: The increase in pollution levels due to significant contributions from external sources, including emissions from nearby states like Punjab and Haryana.  

What are the challenges in Monitoring AQI?

• Inconsistent Data Reporting: There is confusion regarding AQI readings, with some private agencies reporting values exceeding 1,000 while official figures cap at 500. This discrepancy arises from differences in how pollutant concentrations are converted to AQI values based on less stringent national guidelines compared to WHO standards.
• Dependence on External Data: India’s reliance on satellite data from NASA for monitoring fires and pollution limits its ability to independently assess air quality. There is a need for more localized monitoring using Indian satellites that can provide continuous coverage.
• Lack of Comprehensive Frameworks: Current monitoring systems do not adequately account for regional cooperation or comprehensive frameworks that address transboundary pollution issues effectively. This lack of coordination complicates efforts to manage air quality across state lines.