What Is 'Severe Plus,' The New Tag Being Used For Delhi's Hazardous Air Quality?

For the fifth day in a row, Delhi woke up to a blanket of heavy pollution on Monday, with the Air Quality Index (AQI) persistently hovering in the 'severe plus' category, with the city's overall AQI reaching 488.

Areas like RK Puram, ITO, Patparganj, and New Moti Bagh are among the hardest hit in Delhi, with AQI levels of 466, 402, 471, and 488 respectively.

The persistent toxic haze shrouding the city has doctors worried about an increase in respiratory and ocular conditions, particularly in children and the aged.

In recent days, the concentration of fine PM2.5 particles, notorious for penetrating deep into the lungs and triggering health issues, has escalated to levels seven to eight times beyond the government's threshold of 60 micrograms per cubic meter in various parts of Delhi-NCR.

Alarmingly, this is 80 to 100 times over the World Health Organization's recommended safe level of 5 micrograms per cubic meter.

The Central government has put in action the Graded Response Action Plan (GRAP) at its most stringent level in Delhi and neighbouring areas, where the air quality is staying within the "severe plus" category.

What is 'Severe Plus' AQI category

The National Air Quality Index (AQI) was launched by the government in 2014.

The AQI is designed to provide a clear and easily understandable indication of air quality to the general public, encapsulated in a single number, colour, and description.

The AQI considers eight pollutants: PM10, PM2.5, NO2, SO2, CO, O3, NH3, and Pb, and is divided into six categories: Good, Satisfactory, Moderately polluted, Poor, Very Poor, and Severe.

The 'Severe Plus' category represents an AQI level above 450.

The worsening of air quality to 'Severe Plus' category may cause respiratory effects even on healthy people and serious health impacts on individuals with existing lung or heart diseases. The health impacts can be felt even during light physical activities.

Graded Response Action Plan

In view of the deteriorating AQI in the national capital region, the sub-committee of Commission for Air Quality Management (CAQM) decided to invoke Stage IV of the Graded Response Action Plan (GRAP) in the entire NCR with immediate effect on Sunday, in addition to all actions under Stage I, II and III to prevent further deterioration of air quality in the region.

The GRAP is a set of anti-air pollution measures that the Central Pollution Control Board (CPCB) has established. The GRAP has four stages, with Stage IV being the most severe. Stage IV is activated when the Air Quality falls in 'Severe Plus' category i.e. AQI above 450.

"Keeping in view the prevailing trend of air quality, in an effort to prevent further deterioration of the air quality, the sub-committee decided that ALL actions as envisaged under Stage IV of the GRAP i.e., 'Severe+' category (DELHI AQI >450) be implemented in right earnest by all the agencies concerned in the NCR, with immediate effect, in addition to the stage I, II and III actions already in force," CAQM said in a statement.

Eight-Point Action Plan Under GRAP Stage IV

The sub-committee has recommended eight-point action plan to counter the air pollution:

1. Stop entry of truck traffic into Delhi (except for trucks carrying essential commodities/ providing essential services and all LNG/ CNG / electric trucks).

2. Do not permit LCVs registered outside Delhi, other than EVs / CNG / BS-u diesel, to enter Delhi, except those carrying essential commodities / providing essential services.

3. Ban on plying of Delhi - registered diesel operated Medium Goods Vehicles (MGVs) and Heavy Goods Vehicles (HGVs) in Delhi, except those carrying essential commodities / providing essential services.

4. Ban C&D activities also in linear public projects such as highways, roads, flyovers, overbridges, power transmission, pipelines etc.

5. NCR State Govts. and GNCTD may take a decision on discontinuing physical classes even for classes VI - IX, class XI and conduct lessons in an online mode.

6. NCR State Governments / GNCTD to take a decision on allowing public, municipal and private offices to work on 50% strength and the rest to work from home.

7. Central Government may take appropriate decision on permitting work from home for employees in central government offices.

8. State Governments may consider additional emergency measures like closure of colleges/ educational institutions and closure of non-emergency commercial activities, permitting running of vehicles on odd-even basis of registration numbers etc.