New Delhi – Delhi air quality plummeted to hazardous levels on Sunday as the city’s Air Quality Index (AQI) surged to 440, marking the most polluted January day in two years. According to the Central Pollution Control Board’s (CPCB) daily bulletin, the Capital clocked this alarming reading at 4pm, significantly worse than Saturday’s 400 and the highest for the month since January 14, 2024, when it reached 447.
The deterioration in Delhi air quality is particularly unusual for the second half of January, when air pollution typically shows improvement compared to the first half of the month, which generally marks the peak of the winter pollution season.
Historical Context of January Pollution
Sunday’s Delhi air quality crisis represents the joint-worst reading in the second half of January on record. The AQI last touched 440 during this period on January 17, 2019. Historical data reveals that the AQI for the latter half of January peaked at 430 in 2016, 375 in 2017, 403 in 2018, 370 in 2020, 407 in 2021, 387 in 2022, 407 in 2023, 409 in 2024, and 368 last year.
This marks the first time that Delhi air quality has remained at 400 or above for two consecutive days in this period since late January 2016, highlighting the severity of the current pollution crisis.
Meteorological Factors Behind Crisis
Scientists attributed the sharp decline in Delhi air quality largely to slow surface-level winds and a western disturbance that brings moisture and leads to emissions accumulating in the atmosphere. These meteorological conditions created a perfect storm for pollution to concentrate over the National Capital Region.
“We cannot control climate and meteorological conditions. What can be controlled is the emissions being generated at source. Such alarming levels show that our emissions in the region are only increasing and not decreasing,” said Dipankar Saha, former head of CPCB’s air lab.
GRAP Implementation Questions
The pollution crisis has raised serious questions about the effectiveness of the Graded Response Action Plan (GRAP) and ground-level management in controlling Delhi air quality. Experts pointed out that the fresh pollution crisis turned the lens on ineffectiveness of GRAP implementation, including concerns about lifting curbs too early.
“So even with Grap being implemented, it is doing little to control such drastic spikes when winds become calm,” Saha added, highlighting the limitations of current pollution control measures.
The Commission for Air Quality Management (CAQM) imposed Stage 4 of the GRAP curbs on Saturday evening, only after the air quality inched past the 400 mark for the first time this year.
Most Affected Neighborhoods
Several areas experienced extremely hazardous conditions as Delhi air quality deteriorated across the city. Anand Vihar emerged as Delhi’s most polluted neighborhood, recording an AQI of 497 at 12pm—just three points away from the peak of 500.
Other severely affected locations included Mundka and Rohini, both registering an average AQI of 491 each, placing residents at extreme health risk.
Industrial Pollution Sources
Sunil Dahiya, founder and lead analyst at think tank Envirocatalysts, emphasized that little action was being taken against prevalent sources affecting Delhi air quality. “It is clear that while Grap is not working, a key reason why it is not working includes our inability to control sources such as industries and thermal power plants in the National Capital Region,” he stated.
With easterly wind direction, significant pollution originates from Gautam Buddha Nagar and Bulandshahr, where industries are growing year-on-year. The lack of action against thermal power plants in NCR continues to impact Delhi air quality negatively.
Governance and Implementation Gaps
Mukesh Khare, part of the 11-member expert panel formed by the Delhi government in December to tackle air pollution, said such high levels of pollution affecting Delhi air quality in the latter half of January indicate failing governance at the civic level.
“We see policies being made, but implementation remains an issue. At present, around 30% of the pollution in NCR is coming from diffused sources. This includes road dust, footpaths, medians and even waste burning,” Khare explained.
Current Restrictions in Place
Multiple restrictions have been implemented since Friday when GRAP Stage 3 was invoked. These measures include bans on BS-3 petrol and BS-4 four-wheelers in Delhi, Gurugram, Faridabad, Ghaziabad and Gautam Budh Nagar, along with blanket curbs on private construction and demolition.
Under Stage 4 restrictions aimed at improving Delhi air quality, the entry of BS-IV truck traffic into Delhi is restricted. All construction and demolition work is prohibited, while schools up to Class 10 must shift to hybrid lessons.
Supreme Court Intervention
The air quality downturn comes shortly after the Supreme Court pulled up the CAQM for its inability to clearly identify the causes of air pollution in Delhi-NCR. Calling this a “complete failure of duty,” the court directed the statutory body to complete a source-identification exercise within two weeks.
Looking Forward
Forecasts indicated that weather conditions may help clean up Delhi air quality to some extent on Monday, when the AQI may return to the “very poor” zone. However, experts stress that long-term solutions require controlling emissions at the source rather than relying solely on favorable meteorological conditions.
Sunday marked Delhi’s first official “severe” air day of the year and the second-worst air day this winter after December 14’s reading of 461, underscoring the urgent need for effective pollution control measures.
