Delhi’s air quality took a sharp turn for the worse on Tuesday, prompting authorities to invoke Stage III of the Graded Response Action Plan (GRAP) with immediate effect. This comes as the Air Quality Index (AQI) of the national capital breached the 400-mark, reaching 425 at 9 am, and marking the first time this season that Delhi’s air has entered the ‘severe’ category.

Data from the Central Pollution Control Board (CPCB)’s Sameer app revealed that 34 out of 39 active monitoring stations across the city recorded severe AQI levels early Tuesday morning, with several stations reporting readings at the upper end of the scale. Among the worst-hit areas were Bawana (462), Wazirpur (460), and Mundka and Punjabi Bagh (452).

The AQI classification system defines the levels of air pollution as follows:

• 51–100: Satisfactory
• 101–200: Moderate
• 201–300: Poor
• 301–400: Very Poor
• Above 400: Severe

With Delhi’s AQI now in the severe range, authorities have intensified pollution-control measures to mitigate health risks, particularly for children, the elderly, and people with respiratory or heart conditions.

Key Measures under GRAP-III

The Graded Response Action Plan (GRAP) is designed to tackle worsening air quality in Delhi and the National Capital Region (NCR) by progressively tightening restrictions as pollution levels rise. Stage III is the second-highest alert level and includes the following curbs and allowances:

Banned Activities

• Non-essential construction and demolition: This includes activities such as earth excavation, piling, laying sewer lines or electric cables through open trenches, and the operation of Ready-Mix Concrete (RMC) batching plants. These measures aim to curb dust, a major contributor to particulate matter in the air.
• Private BS-III petrol and BS-IV diesel vehicles: Four-wheelers registered in Delhi, Gurugram, Faridabad, Ghaziabad, and Noida using these older emission standards are restricted.
• Diesel goods vehicles: Non-essential BS-IV medium goods vehicles and BS-IV or lower diesel light commercial vehicles registered outside Delhi are banned, except those transporting essential goods or providing essential services.

Advised Measures for Offices and Schools

• Work-from-home or hybrid arrangements: Private companies are encouraged to reduce vehicular emissions by allowing employees to work remotely or adopt staggered shifts.
• School closures for younger students: Classes up to Class 5 are to be conducted online to limit exposure of children to hazardous air.

Exemptions

Certain public projects deemed essential are allowed to continue under strict supervision. These include:

• Railways and metro construction
• Airports and defence operations
• Sanitation and healthcare services

While these activities are exempt from the ban, authorities have instructed that strict dust and waste management protocols be followed to prevent further air quality deterioration.

Reasons for the Pollution Spike

Officials attribute the sudden rise in pollution to a combination of calm winds, low temperatures, and a stable atmosphere, which hinder the dispersion of pollutants across the city. Experts also noted that the haze observed in Delhi is not fog, as it has persisted throughout the day, indicating continuous accumulation of particulate matter.

The deteriorating air quality follows a day of missing pollution data on Monday, when server issues delayed updates for nearly 10 hours—from noon to 10 pm—affecting real-time monitoring and decision-making. Despite this, pollution levels continued to rise, and the AQI crossed the 400-mark by early Tuesday morning.

City-Wide Impact and Public Advisory

The severe pollution alert has prompted authorities to advise residents to limit outdoor activities, particularly those in sensitive groups. People are encouraged to wear N95 masks if venturing outside and to reduce non-essential travel.

The GRAP-III curbs also extend to private transport, construction, and industrial activities, aiming to minimise emissions during peak pollution periods. Staggered office timings and hybrid schooling are intended to reduce congestion and vehicular emissions, which are significant contributors to Delhi’s air pollution.

Looking Ahead

While GRAP-III is a temporary measure, it underscores the urgency of tackling air pollution in Delhi and NCR, a region that regularly experiences hazardous air quality during the winter months. Long-term solutions require coordinated efforts among state governments, local authorities, and residents, including restrictions on older vehicles, control of industrial emissions, and measures to prevent stubble burning in neighbouring states.

Authorities continue to monitor AQI levels across the city, with additional measures likely if the air quality does not improve. Residents are advised to stay updated on the latest advisories and to comply with restrictions to safeguard public health.

As Delhi grapples with its first ‘severe’ pollution day of the season, the GRAP-III restrictions represent a crucial step in mitigating risks and protecting citizens from the immediate health hazards of toxic air.

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