A man sweeps a road near India Gate as the sky after Delhi's air quality turned "severe".

Delhi air pollution: What is GRAP-4 and its restrictions?

What is GRAP-4? An AQI above 400 is considered hazardous, impacting even healthy individuals and posing serious risks to those with existing health conditions.

by · India Today

A thick blanket of toxic smog engulfed Delhi on Monday, reducing visibility and pushing the Air Quality Index (AQI) to 484—the highest recorded this season. Authorities have enforced Stage IV of the Graded Response Action Plan (GRAP), introducing stringent measures to combat the crisis.

The restrictions were announced by the Commission for Air Quality Management (CAQM) as pollution levels breached the 'severe plus' category.

Traffic passes on a road Delhi's air quality turned "severe". (Reuters)

What is GRAP Stage 4?

Introduced in 2017, GRAP is a graded set of measures to control air pollution in Delhi-NCR based on the severity of the AQI.

The plan categorises air quality into four stages:

  • Stage I (poor): AQI 201-300
  • Stage II (very poor): AQI 301-400
  • Stage III (severe): AQI 401-450
  • Stage IV (severe plus): AQI above 450

An AQI above 400 is considered hazardous, impacting even healthy individuals and posing serious risks to those with existing health conditions.

A office goer walks wearing a face mask amidst a thick layer of smog. (AP photo)

Key GRAP Stage 4 restrictions

  1. Entry of trucks into Delhi is banned, except for those carrying essential goods or operating on CNG, LNG, or BS-VI diesel.
  2. Light Commercial Vehicles (LCVs) registered outside Delhi, except those running on EV, CNG, or BS-VI diesel, are barred from carrying essential goods.
  3. Diesel-operated Medium and Heavy Goods Vehicles registered in Delhi (BS-IV or lower) cannot operate, with exceptions for essential services.
  4. Construction and demolition activities, including public infrastructure projects like highways and flyovers, are prohibited.
  5. Schools have shifted to online classes for most students, except for those in classes 10 and 12.
  6. Governments in Delhi-NCR may direct public and private offices to operate at 50% capacity, with the rest working from home.
  7. Additional measures like odd-even vehicle rationing, closure of colleges, and halting non-essential commercial activities are under consideration.

Delhi's AQI worsens

Visibility in some areas, such as Safdarjung airport, dropped to 150 metres on Monday morning.

The AQI, which was 441 at 4 pm on Sunday, climbed to 457 by evening and further worsened overnight due to adverse weather conditions.

With the AQI surpassing 450, CAQM directed immediate enforcement of GRAP Stage IV measures. Physical classes in most schools were suspended, leaving only students in classes 10 and 12 attending in person.