As Delhi gasps for breath beneath a hazardous layer, one of the most spoken topics in the city is AQI (Air Quality Index). While many theories flood social media and citizens measure the air quality index using several machines--a troubling question keeps resurfacing: can the city’s official air quality numbers be trusted?
Behind the daily AQI bulletins lies a network of 38 real-time monitoring stations installed between 2010 and 2018 by three different agencies–the Delhi Pollution Control Committee (DPCC), the India Meteorological Department (IMD) and the Central Pollution Control Board (CPCB). These stations are meant to serve as the scientific backbone of Delhi’s pollution response. But a closer look at them raises serious concerns, pointing to a pattern of non-compliance with prescribed norms.
CPCB guidelines require pollution sampling inlets to be placed away from trees, buildings and major roads to ensure free airflow and representative data. Yet, barring a handful, most stations visited were staggered in by dense vegetation, boundary walls or nearby structures, with branches hanging dangerously close to the inlets. Several stations were also found close to busy roads, contrary to norms that mandate a minimum distance to avoid skewed readings.
Typically housed inside schools, colleges and stadiums, these were barely noticeable. This questionable sighting has fuelled public scepticism, especially on days when residents’ personal air quality monitors recorded AQI levels above 850, while official stations reported far lower figures. With the worsening air crisis in the city, the integrity of the very system measuring the AQI is under scrutiny.
Sprinklers, smog tower yet Anand Vihar air worries locals
Nestled behind a large smog tower and a layer of trees, the Anand Vihar monitoring station was locked from outside when the reporters went for a survey. However, the digital display at the station continued to show real-time updates of key air pollution parameters such as carbon monoxide (CO), and particulate matter (PM2.5). According to a person present inside the smog tower premises, it operates twice a day. The National Capital Region Transport Corporation (NCRTC) has placed water sprinklers at the terrace of its Anand Vihar station.
As part of broader pollution-control measures, water sprinklers have also been set up along the dividers of the main road in Anand Vihar.
Inside the Anand Vihar inter-state bus terminal located behind the monitoring station, a water sprinkler truck was deployed to reduce pollutants. Despite these measures, citizens continue to express concern over the deteriorating air quality. Suman, who came to Delhi from Gorakhpur, said, “When we reached here this morning, we felt a shift in the air quality. Our kids being exposed to such polluted air is a very serious issue. The government needs to work on this,” she stated.
Wazirpur chokes despite daily water sprinkling
The Wazirpur air pollution monitoring station, located in one of north Delhi’s most congested industrial clusters, continues to record some of the worst air quality levels in the capital, even as local authorities routinely deploy mitigation measures in the area. In the first 19 days of the month, the station recorded ‘severe’ air quality on seven days, ‘very poor’ levels on 11 days and ‘poor’ air on just one day. PM10 and PM2.5 remained the dominant pollutants at the site, reflecting the heavy pollution load typical of industrial and traffic-dense neighbourhoods during the winter months.
Wazirpur is a long-established industrial hub, dotted with factories, godowns and small manufacturing units, alongside dense residential colonies. The monitoring station is located within the campus of the Delhi School of Skill and Entrepreneurship (DSSE). However, unlike more insulated sites, it is not surrounded by extensive greenery. Major roads run immediately outside the boundary wall, leaving the station directly exposed to vehicular emissions and industrial dust.
“You will often see water tankers sprinkling water on the main road, especially during the day,” said Ramesh Kumar, a resident who has lived in the area for over two decades. “It helps settle the dust for some time, but the relief doesn’t last very long.” Another resident, Sunita Devi, who lives close to the station, echoed the concern. “The sprinkling happens almost daily, particularly in winter,” she said.
“But with so many trucks and industrial vehicles passing through, the dust comes back within hours.” Locals noted that while daytime measures offer limited relief, pollution levels tend to worsen sharply at night. “At night, there is no sprinkling, and the air becomes much heavier,” said Imran Khan, a shopkeeper in the area. “You can feel the difference when you step outside.”
Like other stations under the Delhi Pollution Control Committee (DPCC), the Wazirpur monitor operates round-the-clock and generates automated air quality data at regular intervals. Despite routine dust suppression efforts, the station’s readings suggest that localised measures alone are insufficient to counter the combined impact of industrial emissions, heavy traffic and unfavourable winter meteorological conditions.
Inside Okhla’s station severe AQI persists even away from roads
The Okhla Phase 2 air pollution monitoring station, located in one of South Delhi’s most industrialised pockets, continues to record persistently high pollution levels despite its relatively insulated setting. On Friday, the station logged an average AQI of 405, placing it firmly in the ‘Severe’ category, underlining the scale of the capital’s winter pollution crisis.
Data from the station shows that pollution levels have remained alarming through most of the month. In the first 19 days alone, the AQI fell in the ‘Severe’ category on five days, ‘Very Poor’ on ten days and ‘Poor’ on four days. Particulate matter PM10 and the finer PM2.5 were identified as the dominant pollutants driving the readings.
Interestingly, the monitoring station is situated within the campus of the Delhi Skill and Entrepreneurship University (DSEU), surrounded by greenery. Tucked away from direct exposure to traffic, it is shielded from the dust and emissions of busy arterial roads outside the campus.
The nearest main road lies around 200 metres away, while the station itself has a monitoring range of about 500 metres. Despite this buffer, pollution levels remain high, suggesting that the problem extends beyond immediate road dust or localised emissions. The station also functions as an ambient noise monitoring unit, capturing data on sound levels in the area alongside air quality parameters.
According to an operator at the site, who works for a private firm managing the station on behalf of the Delhi Pollution Control Committee (DPCC), the facility has been operational for over a decade. “The station runs 24 hours a day and updates pollution data every 15 minutes. Everything is automated. Our role is mainly to ensure there are no technical issues,” the operator said.
The station is managed by two staff members working in shifts. The operator noted that pollution levels typically peak during the night, when atmospheric conditions trap pollutants closer to the ground.
“During the day, civic agencies regularly sprinkle water on roads in and around the area, which helps keep dust levels under control,” he added. The firm currently operates all 24 air quality monitoring stations under DPCC control across Delhi. Observations from the Okhla station, even within a relatively green and protected campus, highlight how widespread and persistent air pollution has become across the city, particularly during the winter months.
RK PURAM masks it well
Walking through the bustling weekly evening market in RK Puram Sectors 1 and 2, it is hard to tell that the area routinely ranks among Delhi’s top five pollution hotspots. However the 400 plus AQI is a reality monitored by the apps.
Delhi Pollution Control Committee (DPCC) has installed an air quality monitoring station in that area which is housed inside the premises of Kendriya Vidyalaya Sector 2, RK Puram. Taking the correspondent towards the monitoring station, the guard at the school gate said, “It’s been almost 10 years since this monitoring station is here but even after so many years, the situation continues to be the same or even worse on some days.”
The correspondent was denied entry to the monitoring station, but a technician explained how the sensors function in the facility. “Two devices mounted on the roof of the small, one-room station measure PM2.5 and PM10 levels respectively,” the DPCC technician said.
Locals said that pole-mounted mist sprays have been fitted on the roads which keep sprinkling water twice a day. “Apart from that, anti-smog guns also go on rounds once in the morning and once in the evening,” a resident of the area said.
Lodhi Road in sordid state of affairs
The India Meteorological Department (IMD) building on Lodhi Road hosts an Air Quality Monitoring Station (AQMS), often listed alongside stations from CPCB, DPCC, and IITM for comprehensive monitoring.
This station is a key part of Delhi’s air quality network, contributing to overall AQI readings and forecasts, but the display showing AQI reading in non-functional. At a time when air quality across the capital has deteriorated to extreme levels, the non-functioning of the display to show AQI data raises serious questions over the seriousness of the authorities, which have been making tall claims to curb air pollution.
The staff at the entry gate restricted this correspondent despite verifying the identity. Senior official Rajendra Kumar Jenamani reached there to meet the correspondent but did not approve the entry. He misled on many fronts and said, “There is no AQI monitoring station here, and the board placed outside is non-functional.” He did not give any specific reason why entry is being denied, whether the AQI monitoring station is inside the premises, or whether the station is working or not.
Misting poles at ITO, yet measures to curb pollution inadequate
The officials at the monitoring station refused to talk to the reporter, citing lack of authority. However, the digital display at the station continued to show real-time updates of key air pollution parameters. Surrounded by trees, the monitoring station is placed adjacent to the Indian National Science Academy’s (INSA) smog tower to curb air pollution. A security guard at the building said the tower operates for around 30 minutes daily.
Across the street from the monitoring station, there are misting poles along the dividers of the Vikas Marg. Adjoining areas such as Tilak Marg, which houses the Supreme Court, and Mathura Road saw water tankers sprinkling water on the streets and on roadside plants.
Deepak Kumar, who works at a nearby tea stall, said he has been suffering from a sore throat and cough. “Burning eyes and breathing difficulties have become the most common topics of discussion among customers these days,” he said.
Disproportionate values of Punjabi Bagh
Housed within the premises of Sarvodaya Kanya Vidyalaya, the monitoring station is surrounded by dense tree cover on three sides, with branches from one tree extending over the unit. Positioned near the school’s boundary wall and barely a few metres from an adjoining road, the setup increases the likelihood of disproportionately recording vehicular emissions and road dust.
On December 20 afternoon at 1.30 pm, at the time of the visit, the monitoring station recorded a value of 311. However, the Sameer app showed that it had gone up to 445 at 4 pm.
All things grey
As the residents of the capital continue to suffer from the increasing pollution levels, it is understood that local mitigation measures such as sprinklers, misting poles and smog towers offer only temporary relief, failing to address the scale and spread of the crisis.
The credibility of the AQI monitoring system is under strain, with official data failing to relate to the on-ground reality often shrouded by tricky placement, underscoring the urgent need for a clearer public accountability.
How is AQI calculated?
Air Quality Index (AQI) is calculated by first converting pollutant concentration levels into sub-indices based on health-based breakpoint ranges. These sub-indices are derived from 24-hour average values, except for carbon monoxide (CO) and ozone (O₃), which use 8-hour averages. The highest (worst) sub-index among the monitored pollutants becomes the AQI for that location. AQI is computed only if data for at least three pollutants are available, one of which must be PM₂.₅ or PM₁₀, with a minimum of 16 hours of valid data. Real-time AQI is generated automatically using running averages.
50 monitoring stations in Past
As per a reply tabled in the Rajya Sabha in 2021, the Centre informed Parliament that Delhi had a total of 50 air quality monitoring stations- 10 manual stations and 40 continuous ambient air quality monitoring stations. The information was shared by the then Minister of State for Environment, Forest and Climate Change, Ashwini Kumar Choubey, in response to a parliamentary question. However, now with the Sameer App, 39 monitoring stations are active in Delhi.
Capital still short of 68 CAQM stations
According to the Central Pollution Control Board (CPCB), a city with a population of five million or more should have at least 16 Continuous Ambient Air Quality Monitoring (CAAQM) stations. With an estimated population of around 33 million, Delhi should ideally have a far larger monitoring network. Going by CPCB’s own guidelines, the capital is short of at least 68 CAAQM stations, despite having more air quality monitors than any other state or Union Territory in the country. The shortfall raises concerns about whether Delhi’s vast and diverse pollution hotspots are being adequately captured and represented in official AQI data. This data was also shared as a response in Rajya Sabha in 2021 by the then minister of environment Ashwini Kumar Choubey.