Mumbai's Climate Plan Turns 3: What Does the AQI Data Show?

The number sounds reasonable until you look at where Mumbai started. In 2019, before the plan existed, the average was 95.9.

Three years. 31,534 CPCB readings. 37 monitoring stations. And the needle moved by 0.1 AQI point.

We pulled every Mumbai reading from the CPCB database to see what the data actually shows since the Mumbai Climate Action Plan (MCAP) went live in March 2022. The answer is not a clean win or a clear failure. It is something more frustrating: a city that wrote the plan, expanded the monitoring, and then watched the air quality go sideways.

What Mumbai Promised

On March 13, 2022, then Chief Minister Uddhav Thackeray launched the Mumbai Climate Action Plan. It was the first of its kind in India.

The document ran 240 pages. It was co-authored by WRI India and C40 Cities, backed by data from multiple municipal departments. Mumbai had joined the C40 Cities network in December 2020, and the MCAP was the tangible output of that commitment.

The plan covered six key areas with 24 priority actions, each with deadlines and financing sources:

For air quality specifically, the plan targeted cleaner fuels, EV adoption, strict construction dust regulation, and better waste management enforcement.

Starting from a 2019 baseline of 23.42 million tonnes of CO2 equivalent emissions (1.8 tonnes per person), Mumbai's political leadership called it a transformation roadmap. BMC Commissioner Iqbal Singh Chahal pointed to Rs 40,000 crore in infrastructure projects already in process.

The question was never whether the plan was ambitious enough. It was whether anything would actually change on the ground.

The AQI Trend: Five Years, One Number

Here is what Mumbai's citywide average AQI looks like year by year, compiled from every CPCB station reporting in the metro area:

Two things jump out.

First, 2022, the year the MCAP launched, was Mumbai's worst year on record at 127 AQI. The plan arrived, and the air got worse.

Second, 2024 pulled the number back to 96, almost exactly where 2019 was. That looks like recovery, but the composition changed: 37 stations were reporting in 2024 versus 10 in 2019. More stations from different neighborhoods, including cleaner coastal areas and new BMC monitors, pulled the average down.

And there is a hole in the middle. 2023 data is entirely missing from the CPCB database for Mumbai. A full year gone. We cannot tell whether 2024's recovery was sudden or gradual, because the bridge year does not exist.

Station by Station: 12 Improved, 10 Got Worse

Citywide averages hide where things actually changed. We compared every station that had at least 30 readings in both periods: pre-MCAP (2019 to 2021) and post-MCAP (2022 to 2024).

The result is a perfect split decision.

The stations that improved are mostly in the northern suburbs: Malad, Mulund, Kandivali, Borivali. The ones that worsened cluster around central and south Mumbai: Worli, BKC, Mazgaon, Deonar. Whether this reflects real changes in local emissions or shifts in construction activity and traffic patterns is hard to tell from AQI data alone. But the geographic split is noticeable.

The biggest surprise is Siddharth Nagar-Worli. A relatively clean station pre-MCAP (84 AQI), it jumped to 117 post-MCAP, a 33-point worsening. Worli is one of Mumbai's most active construction zones, and the MCAP's Air Quality pillar specifically called for "strict regulation and appropriate enforcement mechanism" for construction dust. That mechanism has not shown up in the data.

For a deeper breakdown of Mumbai's stations and seasonal patterns, see our full Mumbai AQI analysis.

The Season That Matters: Winter

Mumbai's air quality problem is a winter problem. June through September, when monsoon winds scrub the air, the city averages 40 to 65 AQI. October through February, it jumps to 130 to 220.

December 2022 was the worst winter month on record: 210 AQI. December 2024 was 150, a meaningful improvement. January 2024 (126) was also the lowest January in our dataset, well below the 2021 peak of 221.

The aggregate winter picture: pre-MCAP (2019 to 2021) winter average was 155 AQI. Post-MCAP (2022 to 2024) it dropped to 143, an 8% improvement. Modest, but real.

The question is whether this reflects MCAP interventions or weather variation. Without isolating for meteorological factors like wind speed and rainfall timing, the causal link is uncertain. What the data does confirm is that 2022's terrible winter did not set a new normal. 2024 pulled back.

How Mumbai Compares to Other NCAP Cities

Mumbai does not exist in isolation. Under the National Clean Air Programme, dozens of Indian cities received targets and (some) funding to improve air quality. How does Mumbai's trajectory compare?

Varanasi is the standout. From 257 AQI in 2017 to 56 in 2024. A city that was as polluted as Delhi now breathes air classified as Satisfactory across the full year. For details on how Varanasi and other NCAP cities performed, see our NCAP scorecard analysis.

Delhi is stuck. Five consecutive years near 210, despite being India's most scrutinized city for air pollution.

Pune mirrors Mumbai: oscillating between 90 and 120 with no clear trend.

Mumbai's net change from 2019 to 2024 is essentially zero. The MCAP may have prevented worsening that would have happened otherwise, but the data cannot confirm that.

Where Mumbai Is Actually Winning: Monitoring Infrastructure

One thing has genuinely transformed since the MCAP launch. Mumbai's monitoring network tripled.

In 2016, only Bandra and Airoli were consistently reporting. By 2019, MPCB stations at the airport, Powai, Kurla, and Colaba came online. Through 2020 and 2021, IITM added research-grade monitors at Mazgaon, Borivali, Deonar, and Malad. By 2024, BMC launched its own stations at Byculla, Ghatkopar, Kandivali West, and Sewri, plus new MPCB stations across Navi Mumbai.

For more context on how India's monitoring infrastructure has expanded nationally, see our monitoring stations growth analysis.

This is not a trivial achievement. You cannot manage what you cannot measure. Three stations gave Mumbai a rough sketch of its air. Thirty-seven stations give it a detailed map.

But the data completeness tells a second story. Not all stations report consistently.

The established MPCB stations report 330 to 360 days per year, close to full coverage. Several of the newer BMC stations report 216 to 288 days, missing 20 to 40% of the year. And the complete absence of any Mumbai station data in 2023 is a gap that no station count can explain.

The GHG Problem Behind the AQI Problem

Air quality is only one slice of the MCAP's scope. The larger challenge is Mumbai's carbon footprint.

According to the MCAP's own analysis (sourced from the Indian Express's reporting on the plan document):

95% of Mumbai's electricity comes from coal-fired power plants. The MCAP targets 50% renewable energy by 2030 and 90% by 2050. That means replacing roughly 12 million tonnes of coal-sourced energy emissions within four years. There is no public evidence that this transition has begun at any meaningful scale.

Between 1980 and 2018, Mumbai lost 40% of its green cover, 81% of its open land, and 30% of its water bodies, while built-up area rose 66%. Temperature has been rising at 0.25 degrees Celsius per decade. The city records an average of 174 caution days and 187 extreme caution days per year based on heat index.

The structural factors working against Mumbai's air quality are not things a plan document can fix. They require sustained investment over decades.

When a City Actually Tries: The Beijing Comparison

Beijing proves that dramatic air quality improvement is possible, but the scale of commitment required is in a different league.

Leading up to the 2008 Olympics, Beijing invested roughly US$17 billion in environmental cleanup. After declaring a "war on pollution" in 2014, the Chinese government enforced coal-to-gas conversion across entire city districts, shut down coal power plants, and replaced 70,000 small coal boilers.

PM2.5 concentration dropped from 89 to 30 micrograms per cubic meter between 2013 and 2022. Heavy pollution days fell from 58 to just 2 by 2024, a 96.6% reduction. Coal's share of Beijing's energy mix dropped from 24% in 2012 to 10% by 2017.

This was not a planning achievement. It was a spending-plus-enforcement achievement, powered by political will that accepted short-term economic pain for long-term livability.

Mumbai's MCAP has the planning part. The spending and enforcement parts remain unclear.

Where This Leaves Mumbai

The data does not support calling the MCAP a failure. Nor does it support calling it a success.

What the three years of CPCB data show is something in between:

Mumbai wrote the plan. It built the monitoring network. It joined the international networks. The next step, the one Varanasi chose and Beijing demonstrated, is to spend the money and enforce the rules with consequences attached.

The MCAP turns four next March. Four years of CPCB data will be a more definitive test than three. But the 2024 numbers suggest that the direction is correct, even if the pace is not.

Check Mumbai's current air quality for today's latest readings across all 37 stations.

*Data for this analysis was sourced from CPCB station readings maintained in the aqinow.co database (31,534 readings from 2016 to 2024) and the Mumbai Climate Action Plan as reported by the Indian Express and documented on Wikipedia. Beijing air quality data sourced from Wikipedia.*