From 8 am on Monday, as a thick layer of smog enveloped the Delhi-National Capital Region, stage-IV of the Graded Response Action Plan was put into action.

This came the day after the Air Quality Index slid into the “severe+” category, breaching the 450 mark. An AQI of more than 400 “may cause respiratory impact even on healthy people, and serious health impacts on people with lung/heart disease”, warns a release from the Ministry of Environment, Forest and Climate Change. “The health impacts may be experienced even during light physical activity.”

An AQI below 100 is considered satisfactory, but even that may cause breathing discomfort to sensitive people.

GRAP is a series of emergency measures that are put into place by the Commission for Air Quality Management as pollution levels rise to specified measures in the Delhi-NCR – which consists of Delhi and parts of Haryana, Uttar Pradesh and Rajasthan – to prevent the air quality deteriorating even further.

GRAP stages

There are four stages of GRAP. Stage-IV is the highest. It is implemented when the AQI climbs to more than 450. It requires almost all school classes to be held online even as it is recommended that offices work on half strength.

All construction activities even of highways and roads are banned; trucks are prohibited from entering the National Capital Region except if they are carrying essential commodities or running on clean fuels.

State governments are urged to consider additional measures such as shutting down non-emergency commercial activities and enforcing odd-even schemes for vehicles. This means that private vehicles with plates ending with odd numbers can operate only on odd dates, while those with even registration numbers can operate on the others.

As stage-IV of GRAP goes into effect, the measures required under previous stages remain in place.

Stage-I is ordered when the AQI is poor (between 210-300). It involves measures such as the mechanical sweeping of roads and sprinkling water on them to keep the dust from rising. It also bans some kinds of construction and demolition activities.

Stage-II is put into place when the AQI is in the “very poor” category (301-400). It entails ensuring uninterrupted power supply to discourage the use of alternate power arrangements such as diesel generator sets that cause pollution and increasing parking fees to discourage private transport.

Stage-III, implemented when the air quality is in the “severe” category (401-450), directs that all mining and stone crushing activities in the region be shut down, among other actions.

Origins of GRAP

GRAP has its roots in a list of measures to mitigate air pollution that the Central Pollution Control Board submitted to the Supreme Court in 2016. After they were approved by the Supreme Court, they were notified the next year by the Environment Ministry as the Graded Response Action Plan.

The Supreme Court mandated that the Environmental Pollution (Prevention and Control) Authority should implement these measures.

In 2021, the Commission for Air Quality Management in NCR and Adjoining Regions was established to ensure “better co-ordination, research, identification and resolution of problems” about air quality, its website says.

The Environmental Pollution (Prevention and Control) Authority was dissolved and the commission became the single agency tasked with containing air pollution in the National Capital Region.

In 2022, the administration of GRAP was modified. Previous versions of GRAP were enforced based on the levels of particulate matter – fine matter in the air that contributes to air pollution.

Now, the Air Quality Index, which counts other pollutants too, has become the measure for air pollution and to implement GRAP.

The previous versions of GRAP were reactive. After 2022, the air quality management commission made GRAP measures preemptive based on AQI predictions.

Why has it not worked?

In a piece in Down to Earth, Sunita Narain, the director general of the Centre for Science and Environment, said that GRAP was supposed to be “an emergency alert system”. It laid down urgent steps to be taken when pollution levels peaked. But “it has become the only time we act, which, obviously, is too little and too late”, she noted.

Tackling air pollution requires a constant, comprehensive approach, rather than implementing emergency short-term measures. For instance, as Shambhavi Shukla of the Centre for Science and Environment noted in another piece in Down to Earth, vehicular pollution, which contributes in a major way to the declining AQI, requires year-round action. This would include policies disincentivising private vehicles and overhauling the public transport infrastructure instead of short-term steps like odd-even.

The Supreme Court has criticised the delays in implementing stage-IV of GRAP and the lack of coordination between the various agencies and states involved in pollution control in the National Capital Region.

In addition, experts note that during winter months, temperature inversions can trap pollutants close to the ground, worsening air quality regardless of the measures that have been implemented.