Mumbai Sweats, Delhi Braces For Winter — Yet Both Choke On Smog: Whose AQI Is Worse? | Mumbai-news News

Last Updated:October 22, 2026, 10:09 IST

Delhi and Mumbai have nearly identical AQI readings, but what is keeping pollution levels high in both cities? Slower winds, seasonal changes and construction dust offer some clues

Mumbai and Delhi are often compared over infrastructure, economic growth and their ambitions to become global powerhouses. Now, air pollution has become another point of comparison, with the two cities recording almost identical Air Quality Index (AQI) readings in the latest figures provided.

Mumbai registered an AQI of 164, while Delhi recorded 165. The reported wind speed in Mumbai was 17.6 kmph, compared with 8.3 kmph in Delhi.

The comparison has fuelled discussion about Mumbai’s deteriorating air quality, particularly as the city has reportedly recorded AQI levels similar to or higher than Delhi’s for four consecutive weeks.

CM Fadnavis Faces Online Criticism

The comparison between Mumbai and Delhi’s air quality has also surfaced in a social media exchange involving Maharashtra Chief Minister Devendra Fadnavis. CM Fadnavis posted on X that he had met President Droupadi Murmu at Rashtrapati Bhavan in New Delhi and invited her to attend the hoisting of the Dharmadhwaj for the Nashik-Trimbakeshwar Simhastha Kumbh Mela 2027.

Responding to the post, a social media user @Pskc1990 questioned whether Chief Minister Devendra Fadnavis had discussed Mumbai’s worsening air quality with the President, while criticising the alleged cutting of trees in Nashik for the 2027 Kumbh Mela preparations. The user also raised concerns about the environmental impact of El Niño and warned that rising pollution could make commuting increasingly hazardous for residents of Mumbai and Thane. The comment accused the government of prioritising religious event preparations at the expense of green cover.

Delhi Vs Mumbai AQI: What Do The Numbers Reveal?

The reported readings of 164 in Mumbai and 165 in Delhi place both cities in India’s ‘moderate’ AQI category for that snapshot. However, Delhi’s air quality was separately reported to have deteriorated into the ‘poor’ category on Wednesday, when the AQI crossed the 200 mark.

Wind speed is one factor influencing pollution levels. Mumbai’s reported wind speed of 17.6 kmph was more than twice Delhi’s 8.3 kmph. Stronger winds can help disperse pollutants, while slower winds may allow them to accumulate. However, the effect also depends on wind direction, atmospheric stability and the amount of pollution being emitted.

Delhi’s post-monsoon pollution is influenced by vehicle exhaust, industrial emissions, construction dust, waste burning and seasonal crop-residue fires. Mumbai faces its own challenges, including dust from construction and redevelopment, vehicle movement and weather conditions that can limit the dispersion of pollutants.

Delhi Pollution: Dussehra Celebrations Add To Seasonal Concerns

Delhi’s latest deterioration in air quality coincided with Dussehra celebrations on Tuesday. Ramleela events, the burning of effigies of Ravana, Kumbhakarna and Meghnad, and fireworks at several venues formed part of the festivities.

Fireworks can release particulate matter and other pollutants into the atmosphere. However, the extent to which Dussehra celebrations contributed to Wednesday’s smog has not yet been established.

The seasonal decline in Delhi’s air quality is also associated with falling temperatures and atmospheric conditions that can restrict pollutant dispersion. Emissions from vehicles, construction sites, industries and waste burning continue to add to the pollution burden.

Stubble Burning Remains A Concern

Farm fires in neighbouring states are another potential contributor as the paddy harvesting season progresses. Earlier this month, the ICAR-Indian Agricultural Research Institute detected 19 farm-fire incidents across six monitored states. Punjab and Uttar Pradesh accounted for seven incidents each, followed by four in Madhya Pradesh and one in Haryana.

Farmers burn crop residue to clear their fields for the next crop. The resulting smoke can travel across state boundaries, but the impact on Delhi depends on the number and location of fires, wind direction and prevailing atmospheric conditions.

Consequently, the presence of farm fires alone does not establish how much they contributed to Delhi’s pollution on a particular day.

Falling Temperatures Could Make Pollution Harder To Disperse

Delhi’s air quality concerns are unfolding alongside a decline in temperatures as winter approaches. On Tuesday, Safdarjung, the capital’s primary weather station, recorded a maximum temperature of 31.8°C and a minimum of 17.7°C. Both readings were slightly below normal.

Seasonal atmospheric changes can reduce the dispersal of pollutants, allowing emissions from multiple sources to accumulate closer to the ground.

The Air Quality Early Warning System (AQEWS) forecast cited in the supplied information indicated that Delhi’s air quality was likely to remain in the ‘poor’ category through October 23. The outlook for the following six days also pointed to poor conditions.

Delhi Invokes GRAP-1 As Air Quality Deteriorates

As Delhi’s AQI entered the ‘poor’ category, the Commission for Air Quality Management (CAQM) invoked Stage I of the Graded Response Action Plan (GRAP) across the National Capital Region (NCR), with immediate effect, as reported by The Times of India.

GRAP is a set of emergency measures designed to prevent air pollution from worsening. Restrictions become progressively stricter as air quality deteriorates.

What Restrictions Apply Under GRAP-1?

The Stage I measures described in the supplied information include restrictions on certain pollution-generating activities and tighter enforcement of existing controls.

• Coal And Firewood In Tandoors: Their use as fuel in tandoors at hotels, restaurants and open eateries is prohibited under the cited measures.
• Diesel Generator Sets: Their use is restricted, with exemptions for emergency and essential services as specified under the plan.
• Dust Management: Agencies are expected to strengthen dust-control measures and address pollution from construction and road dust.
• Compliance And Enforcement: Authorities across the NCR have been directed to implement the applicable measures immediately and prevent further deterioration in air quality.

The CAQM has also urged residents to follow the restrictions and cooperate with enforcement agencies.

How Are GRAP Stages Triggered?

The stages are linked to the severity of air pollution:

• Stage I: ‘Poor’ AQI, between 201 and 300.
• Stage II: ‘Very poor’ AQI, between 301 and 400.
• Stage III: AQI between 401 and 450.
• Stage IV: AQI above 450.

The restrictions become more stringent as pollution levels rise.

Delhi’s Winter Action Plan

The GRAP measures come days after the Delhi government announced its winter action plan to address seasonal air pollution. According to the supplied information, the plan is scheduled to run from November 1 to February 28. It includes a proposed restriction on the entry of vehicles registered outside Delhi that do not meet BS-VI emission standards.

The government has also announced a ‘No PUC, No Fuel’ policy, under which vehicles without a valid Pollution Under Control (PUC) certificate will not be allowed to purchase fuel at petrol pumps.

Other announced measures include restrictions on construction and demolition activities, checks on the transportation of construction materials, road-dust control and efforts to encourage public transport and electric buses.

Mumbai Pollution: Construction Dust Comes Under BMC Scrutiny

Mumbai’s deteriorating air quality has prompted the Brihanmumbai Municipal Corporation (BMC) to intensify action against construction sites that violate pollution-control requirements. The civic body recently issued a stop-work notice to a demolition site in Oshiwara, Andheri West, and imposed a penalty of Rs 35,000, as reported by Hindustan Times.

The action followed complaints about dust spreading across the neighbourhood. The BMC identified several alleged violations, including inadequately covered construction materials and debris, loose soil and debris dumped on roads and footpaths, uncovered cutting and drilling operations, and the absence of an effective dust-extraction system and a vehicle tyre-washing facility.

The notice was issued under Section 354A of the Mumbai Municipal Corporation Act, 1888. The civic body also directed the local police to monitor compliance, according to a media report.

Dust from excavation, demolition, material handling, debris transportation and vehicle movement at construction sites is a significant source of local pollution. The BMC’s actions have therefore placed construction and redevelopment projects under closer scrutiny.

Mumbai’s 28-Point Construction Pollution Framework

In November 2025, the BMC introduced a 28-point framework for dust and pollution control at construction sites. The requirements include real-time air quality monitoring and measures to manage dust generated by excavation, demolition, the handling of building materials and the transportation of debris.

The civic body’s standard operating procedure for implementing GRAP also provides for Stage IV measures if Mumbai’s city-level or local-area AQI remains above 200 for three consecutive days. Depending on pollution levels and compliance, construction activity may be restricted or suspended.

Can Developers Seek Extensions If Construction Is Halted?

Pollution-control action can affect construction schedules, raising questions about whether developers can obtain additional time to complete projects. Legal experts have said that developers may be eligible for an extension under Section 6 of the Real Estate (Regulation and Development) Act, 2016. The provision allows the Maharashtra Real Estate Regulatory Authority (MahaRERA) to extend a project’s registration on grounds of force majeure, generally for up to one year. Any further extension would depend on the circumstances and applicable guidelines issued by the Central or state government.

Nilesh Gala, an advocate at the Bombay High Court, explained the distinction between delays caused by a developer’s own violations and those resulting from a general government-imposed suspension. “When a developer violates air quality norms, they are not eligible for a construction timeline extension, as the delay results from their own violation. However, when the authorities announce a general suspension of construction activities, the case may be eligible for an extension of the construction timeline,” Gala said.

BMC Temporarily Suspends Rule Affecting Architects

The BMC has also temporarily suspended a rule that made architects and licensed surveyors accountable alongside developers for air pollution at construction sites.

The decision followed a meeting between architects’ representatives and the civic administration on October 8. The Council of Architecture had opposed a September 2 circular that provided for the suspension of licences for failure to implement pollution-control measures.

The temporary suspension provides interim relief to architects and licensed surveyors while the issue remains under consideration.

What Is Driving Mumbai’s Pollution?

Apart from construction dust, experts have pointed to weather conditions that may be making it harder for pollutants to disperse.

Atmospheric scientist Gufran Beig, chair professor at the National Institute of Advanced Studies (NIAS-IISc), linked the rise in pollution partly to the prevailing El Niño pattern, a climate phenomenon associated with unusually warm sea-surface temperatures in the central and eastern equatorial Pacific Ocean. “This year, Mumbai is experiencing an El-Nino pattern of climate, as a result of which the wind speed has slowed down tremendously, while it is hot and humid. This factor is preventing air circulation and, as a result, pollutants are getting settled in the lower atmosphere, leading to a rise in pollution,” Beig told The Indian Express.

The relationship between El Niño and Mumbai’s local pollution levels depends on several meteorological factors. Wind speed, temperature, humidity and atmospheric circulation can influence how pollutants behave, while construction and transport continue to generate emissions.

The BMC has consequently stepped up scrutiny of construction and redevelopment projects as the city deals with worsening air quality.

Mumbai Weather Forecast Today

The India Meteorological Department (IMD) has forecast hot and humid conditions in isolated pockets of Mumbai, Thane, Palghar and Raigad on October 22. Dry weather is expected across these districts from October 23 to 25.

Mumbai has been experiencing hot conditions. On Wednesday, the IMD’s Colaba observatory recorded a minimum temperature of 27°C, while Santacruz registered 24.8°C.

Although Mumbai and neighbouring districts are expected to see dry weather later in the week, parts of the Konkan region are forecast to receive rain.

Rain Forecast For Ratnagiri And Sindhudurg

Ratnagiri is forecast to receive light rain or thundershowers on October 22, followed by light to moderate rain or thundershowers on October 23. Sindhudurg is likely to receive light to moderate rain or thundershowers forecast for October 22 and 23. Both districts are expected to experience dry weather on October 24 and 25, according to the IMD forecast.

Several other parts of Maharashtra are also likely to remain dry over the five-day forecast period. Dhule, Nandurbar, Ahilyanagar, Pune and Solapur, along with several districts in the Marathwada region, are expected to experience predominantly dry weather. Isolated rain or thundershowers are forecast in some other districts on specific days.

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