Enviornment Prelims cum Mains

Remote sensing to detect vehicular pollution in Delhi

The News

  • In a step to curb vehicular pollution in Delhi, the International Centre for Automotive Technology will implement remote sensing technology for screening of pollution from on-road vehicles.


  • The Supreme Court-appointed Environment Pollution (Prevention and Control) Authority has been suggesting steps to tackle air pollution in general under the framework of graded response action plan in Delhi-NCR region.
  • The landmark Vardhaman Kaushik v/s Union of India case led to the formulation of GRAP (Graded Response Action Plan for Delhi & NCR) by CPCB.
  • While GRAP is post-mortem in approach, EPCA felt the need for a “preventive plan” to tackle the problem of air pollution in Delhi-NCR in the long run.

Need for Remote-sensing Technology as Compliance strategy for Vehicular Pollution

  • Thus, the apex court had directed the appointment Environment Pollution (Prevention and Control) Authority to make recommendations to tackle air pollution in Delhi-NCR in the long run.
  • Accordingly, the EPCA has directed the International Centre for Automotive Technology to deploy remote sensing technology to measure the amount of pollution each vehicle causes as it enters Delhi.
  • In the initial stages of the study, ICAT has tested around 70,000 vehicles with more number of vehicles set to be monitored.
  • Current system not really working:
    • The current vehicle inspection system involves Pollution Under Control Certificate (PUC) which was originally designed for older technologies.
    • Further, according to data only 23% of the vehicles in Delhi undergo PUC tests and thus lack compliance.
    • However, the on-road fleet in Delhi has moved towards BS-IV compliance.
    • Further, with BS-VI technology for new vehicles, Smart monitoring of on-road emissions has become inevitable.
  • Thus remote sensing-based monitoring of vehicular pollution of on-road fleet is the need of the day.

About Remote Sensing-based Monitoring


  • Under remote sensing technology, a light source and a detector is placed on the side of the road or at a height to transmit a laser beam.
  • The laser beam thus transmitted can measure the exhaust emissions remotely via spectroscopy as vehicles pass by and cross the light path.
  • The technology detects the exhaust plume of the vehicles and measure opacity, nitric oxide, carbon monoxide, hydrocarbons, and carbon monoxide in 0.5 seconds.
  • It can record emission rates from thousands of individual vehicles along with speed and acceleration across all driving conditions.
  • Further, a camera captures the image of the vehicle’s number plate to identify the make, model, certified emission standard, fuel type, rated power and other details.


  • Remote sensing helps to detect individual high-emitting vehicles.
  • It can help improve compliance in cases of tampering of emission control systems by the vehicle owner.
  • As a result, there is no scope of fraud like in the PUC system.


Comprehensive Action Plan and Vehicular pollution

  • In its Comprehensive Action Plan, EPCA has identified 5 key sources of air pollution in Delhi
  1. Vehicles
  2. Combustion in power plants and industries using dirty fuels, like pet coke, coal and biomass
  3. Garbage burning, both in landfills and other places
  4. Dust management on roads, construction sites etc
  5. Crop residue burning
  • Primarily the Comprehensive Action Plan provides for a compliance strategy for Delhi and NCR to meet clean air standards.

Actions to reduce vehicular emissions

  • For New Vehicles
    • Implementation of BS VI fuel and emission standards.
    • Expand CNG programme across NCR including introduction of H-CNG.
    • Introduce battery operated vehicles in targeted segments of two-wheelers, three-wheelers and buses.
    • Install vapour recovery systems to reduce benzene emissions in NCR.
  • For Vehicles on-road
    • Tighten PUC norms for post-2000 vehicles
    • Link PUC certificates with annual vehicle insurance to ensure 100 per cent compliance
    • Divert truck traffic
  • Strategies to reduce vehicle numbers on roads
    • Improve Public transport.
    • Augment the service of Metro for carrying more passengers
    • BRTS to be implemented in targeted high frequency routes.
    • Fare integration and common ticketing by introducing common mobility cards.
    • Prepare and implement zonal plans for developing a Non-motorized transport network.
    • Parking policy to reduce congestion and pollution.
    • Traffic management: Introduce early alarm system during traffic congestion.

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