What is happening in Mumbai?

Mumbaikars are waking up sick with the same set of problems: sore throat, dry cough, burning eyes, blocked nose, and a heavy feeling in the chest. Doctors and residents blame these problems on the dirty air, as the city's Air Quality Index(AQI) has been in the "unhealthy" range, around 230-280 on some days, indicating high levels of fine dust and smoke (PM2.5 and PM10). When AQI reaches such a level, even healthy people may have irritation after some time outdoors, while children, the elderly, and those with asthma or heart problems are at a much greater risk of catching infections and respiratory distress.

The reports on 28 November, Mumbai’s air quality was a serious concern, with the overall AQI at 281, officially falling in the “unhealthy” category. It notes that the city woke up to thick smog, and neighbourhoods such as Nagpada, Mazgaon, Deonar, and Malad were among the worst hit, consistently showing poor readings. The report adds that the BMC responded by enforcing GRAP‑4 measures like extra road cleaning, strict monitoring of construction activity, and fines for polluting industries, even issuing stop‑work notices to 53 construction sites blamed for worsening air quality.

What is AQI and the Rise of AQI in Mumbai

The Air Quality Index (AQI) is a scale used to measure and communicate how polluted the air is or is expected to become. It provides insights into the levels of key pollutants in the air, such as particulate matter (PM10 and PM2.5), nitrogen dioxide, sulphur dioxide, carbon monoxide, and ozone.

The AQI scale ranges from 0 to 500, with higher numbers indicating higher levels of pollution and a greater potential for adverse health effects.

The major air pollutants in Mumbai include PM2.5 and PM10, which emanate from vehicles, construction, industries, waste burning, and road dust. PM2.5 is especially dangerous because its microscopic size enables it to pass by the body's natural defences and penetrate deep into the lungs and even enter the bloodstream, leading to respiratory infections, cardiovascular disease, and long-term damage to organs.

Air quality in Mumbai drastically deteriorated in November 2025, with the city recording some of its worst pollution readings in recent years. According to historical analysis, on 26 November 2025, Mumbai recorded its highest AQI for this date in five years and touched 225 in the "Severe" category, while the readings in the last week of November frequently fluctuated in the range of 200-280, with some hotspots like Mazgaon reaching 305 on 11 and 24 November. During the last 24 hours of 27 November, Mumbai's AQI touched a high of 262 at 4 AM and dipped to a low of 186 at 4 PM both figures still in the "unhealthy" zone. 

Putting it in perspective, data for the year 2025 shows that not a single day out of the 331 days so far has met the safe air quality limits set by the WHO, 61% of days recorded "Unhealthy" air, 25% recorded "Very Poor," and 14% were "Severe." October 2025 had already emerged as Mumbai's most polluted month of the year until November took over. 

Manoj Kumar, Analyst at CREA, said, “October 2025 stands out as Mumbai’s most polluted month so far this year, with air quality levels peaking across several parts of the city. Between October 18 and 22, 19 stations recorded their highest daily PM2.5 levels and seven stations their peak PM10 levels since January.” He added that with the festive season in full swing, Mumbai’s air quality had declined further, exposing people to unhealthy pollution levels. “While celebrations draw more people outdoors, the air remains unsafe to breathe. It’s crucial for authorities to address not just seasonal pollution spikes but also everyday sources like construction dust, traffic emissions, and other contributors that steadily degrade air quality. Protecting public health must remain at the heart of the city’s response,” Mr. Kumar said.

All these factors combined to make the air quality in Mumbai deteriorate sharply in November 2025. Construction activities from various big projects involving metro lines, coastal roads, and redevelopment schemes were kicking up a lot of dust. 

The roads had opened once the monsoon was over, so emissions from vehicles and diesel generators began again. Industrial fumes from refineries along the eastern corridor near Mahul and open burning of garbage at dumpsites like Deonar continued unabated. The weather made things worse: La Niña conditions weakened the sea breeze that normally cleanses Mumbai's air; wind speeds fell to almost zero in large areas of the city; inversion in temperature at night trapped pollutants close to the ground, preventing them from rising and dissipating into the atmosphere. High humidity coupled with stagnant air resulted in thick smog hanging over the city day after day.

The Ethiopian Volcanic Ash Controversy

When pollution levels began spiking in late November, the Maharashtra government first sought to blame volcanic ash drifting from the Hayli Gubbi volcanic eruption in Ethiopia on 23 November, producing a plume rising nearly 14 km into the atmosphere. However, this explanation was summarily dismissed by the Bombay High Court. Chief Justice Shree Chandrashekhar said: "That eruption happened only two days ago. Even before that, if one stepped out, visibility in Mumbai was poor beyond 500 metres." The court mentioned that Mumbai's AQI had been in the "very poor" category well before the volcanic event, thus stressing the fact that local pollution sources, not volcanoes far away, were the main contributor. 

SAFAR research cited in expert analysis mentions that though volcanic plumes rise normally above 15 km and rarely affect the surface air quality, a brief intrusion cannot be completely ruled out under favourable transport winds. However, the key contributor to poor Mumbai air this season remains "persistently low wind speeds combined with high humidity, which trap pollutants and create recurring haze."

How Many Trees did Mumbai Lose in 2025 and Their Role in Pollution

Without a substantial rise in the green cover and proper urban planning, Mumbai seems to continue losing an alarming number of trees in 2025. Between 2018 and 2023, at least 21,028 trees were axed across the city for infrastructure projects like the Mumbai Metro, Coastal Road, and Goregaon-Mulund Link Road. In 2025 alone, the BMC proposed the cutting of 1,244 trees for the Coastal Road project extension from Versova to Bhayander, besides another 706 trees that are expected to be axed along the eastern freeway to make way for a 12.95 km elevated corridor to connect Ghatkopar to Mulund. The most disturbing development, however, has been the threat to an estimated 9,000 mangrove trees directly by the Coastal Road Phase 2 project, besides around 51,000 trees falling within its "influence zone." Environmental activists contest the BMC's claim of having planted 20,044 new trees in 2024–25, pointing out that the city showed no net improvement in the number of trees across all administrative wards, while its compensatory afforestation had failed abysmally in the past-only 50% of the 20,460 trees planted as compensation for Mumbai Metro survived, and only 21% of the 21,916 trees transplanted between 2018–2023 survived. 

Trees have a very critical role in mitigating air pollution, particularly by capturing particulate matter (PM2.5 and PM10). Research has shown that tree leaves-which possess a positive charge and have waxy, randomly-oriented surfaces-naturally attract and trap negatively-charged particulate matter responsible for asthmatic attacks and respiratory diseases. Studies have estimated that when 20–30% of a city's area is covered by trees, particulate pollution can be reduced by almost 24%. However, most Indian cities, including Mumbai, have tree cover between 7–15%, which is far below the threshold for protection against pollution. A 2016 University of Exeter study correlated higher tree density in urban neighbourhoods with lower asthma incidence, an illustration of the health benefits of urban forests. As for Mumbai in particular, studies estimated that existing trees provide approximately 13 billion dollars' worth of ecosystem services annually, including pollution removal and climate regulation. As trees are cut down for construction and replaced by concrete and cement, which absorb and radiate, the city would lose not only its natural filtering of air but also the ability to cool itself, creating an environment where pollutants accumulate and concentrate at ground level, making November 2025's pollution crisis worse than it would have been with intact tree cover.

Why Civic Sense is the Key to Combating Air Pollution in Mumbai

The pollution crisis engulfing Mumbai in November 2025 is not merely a technical problem that can be solved by government orders or construction bans-it is fundamentally a crisis of civic consciousness. While the BMC issues stop-work notices to 53 construction sites and implements GRAP-4 measures across the city, enforcement fails the moment the authorities' backs are turned. Construction sites continue dumping uncovered debris at night, trucks bypass checkpoints carrying loose material, builders bribe officials to look the other way, and residents continue burning plastic and waste in neighbourhoods despite knowing it poisons the air everyone breathes. People who complain about sore throats and pollution are often the same ones idling their car engines at traffic signals, burning leaves in their building compounds, and ignoring "no honking" signs that contribute to dust resuspension. Communities that blame "the government" for high AQI but throw plastic into streets, don't plant trees on their properties, and demand the latest construction projects regardless of environmental cost are fundamentally contradicting themselves. Without civic sense-the understanding that individual actions have collective consequences and that clean air is a shared responsibility, no policy, court order, or pollution-control measure can succeed. 

A city fights air pollution, not just through enforcement, but also through active citizens who voluntarily desist from burning garbage, inform the authorities about polluting industries, use public transport, plant trees, get construction sites to follow basic dust-control rules, and take responsibility for their own and their neighbours' actions. The residents of Mumbai need to recognize that every minor decision-from the disposal of garbage to whether or not infrastructure projects that chop down mangrove forests are supported-either exacerbates or ameliorates the shared air that everyone breathes. Till civic sense replaces apathy, indifference, and the culture of looking the other way, even the most stringent pollution laws will remain a paper exercise, and the November 2025 pollution crisis will replay itself every winter, with growing intensity each year.