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Air Quality Hotspot Forecasting and Early Warning System

Solution Overview

Mumbai is implementing an air pollution hotspot-based forecasting system designed to provide ward and zonal-level air quality predictions across the metropolitan region.[4] The Indian Institute of Tropical Meteorology (IITM) through its System of Air Quality Forecasting and Research (SAFAR) program serves as the lead agency for developing this Air Quality Forecasting and Early Warning System, with support from the Maharashtra Pollution Control Board (MPCB) and the Municipal Corporation of Greater Mumbai (MCGM).[4] This approach aims to inform the public and guide emergency response measures through spatially granular air quality forecasts.[4]

Technical Components

The Air Quality Early Warning System (AQEWS) integrates multiple data streams including weather forecasts, satellite-based Aerosol Optical Depth (AOD) measurements, and ground-level monitoring from 24 air quality monitoring stations across Mumbai, Mahape, Vasai, Nerul, and Kalyan.[5] Within Greater Mumbai specifically, the system utilizes 20 air quality monitoring stations at locations including Navy Nagar, Malad West, Borivali East, Deonar, Powai, Mulund West, Bandra Kurla Complex, and Chakala.[5] IITM has integrated satellite AOD data—which measures the hazy effect aerosols create in polluted air—along with historical data from a network of 420 air quality monitoring stations across India to power these early warning systems.[5] The forecasting system relies on pinpoint accuracy, starting with precise weather forecasts as a foundation, according to IITM scientist Sachin Ghude.[5] Mumbai currently operates 28 Continuous Ambient Air Quality Monitoring System (CAAQMS) stations, with five managed by the Brihanmumbai Municipal Corporation (BMC), nine by IITM, and 14 by MPCB.[1] Each CAAQMS station costs ₹9 crore and monitors PM2.5 and PM10 concentrations, as well as levels of carbon monoxide, sulphur dioxide, nitrogen oxides, ammonia, and ozone.[1] These stations also measure wind direction, wind speed, ambient temperature, relative humidity, solar radiation, and rainfall.[1] All CAAQMS stations connect to a server, with readings accessible through the Central Pollution Control Board (CPCB) website or CPCB's Sameer app.[1] The performance of these early warning systems can be enhanced with Low-Cost Sensor (LCS) devices, which can provide an even more granular picture of air pollution and support hyperlocal mitigation measures within short time frames.[5]

Implementation Details

The Mumbai Climate Action Plan targeted implementation of the Air Quality Forecasting and Early Warning System for the short-term period of 2022-2025.[4] The AQEWS for Mumbai was rolled out during the India Clean Air Summit (ICAS) in 2023, organized by the Centre for Air Pollution Studies (CAPS) at the Center for Study of Science, Technology and Policy (CSTEP) in Bangalore.[5] The system became accessible through a dedicated web portal at ews.tropmet.res.in/mumbai/index.php.[5] Since 2022, the number of monitors in Mumbai increased by 50% to 30, providing better ground-level reporting that helps identify local pollution sources.[2] An additional 15 CAAQMS stations were planned for installation in the Mumbai Metropolitan Region (MMR) before the start of winter, with work orders issued for phased delivery starting the following month.[6] The expansion plan allocated three additional stations each to Thane, Vasai-Virar, and Kalyan-Dombivali areas, while two stations each were designated for Mira-Bhayander, Ulhasnagar, and Bhiwandi Nizampur areas.[6] Each of these new stations carries a cost of Rs 9 crore.[6] Mumbai's Climate Action Plan also proposed expanding the real-time air quality monitoring network to cover all wards of the city by 2025, with MPCB and MCGM as lead agencies and IITM (SAFAR) as supporting agency.[4] The city aimed to establish a network of 50 real-time air quality monitoring stations by 2025 as part of its climate action plan targets.[4] The MCAP included developing a high-resolution emissions inventory and source apportionment study for Mumbai in the short-term period of 2022-2025, led by MPCB and the National Environmental Engineering Research Institute (NEERI).[4] The plan also proposed increasing the number of monitoring stations such as CAAQMS equipped with low-cost indigenous sensors and real-time monitoring technology based on CPCB criterion for site location by 2022-2027.[8] Currently, Mumbai has 11 MPCB CAAQMS and 9 SAFAR CAAQMS stations installed, with 5 SAFAR CAAQMS stations proposed.[8] The MPCB operates 12 mobile vans positioned to monitor pollution levels at various sites, which help monitor pollution in hotspots since AQMS cannot be set up overnight.[9] These mobile vans are stationed near heavy traffic junctions like Wadala and Andheri, as well as near the Deonar and KanjurMarg dumping grounds.[9] Data from the mobile vans is shared with local ward offices for action against any polluting body.[9] The BMC currently has only one mobile van for monitoring pollution levels at pollution hotspots or from places where specific complaints are received, which was dysfunctional and being repaired.[9] The BMC planned to consolidate with each ward and department to assess commitment from each level, after which a comprehensive action plan would be drawn up in conjunction with the requirements of forecasting models.[7] The broader SAFAR program implementation plan included installation of meso-urban observation networks in major metropolitan cities and development of high-resolution dynamic emission inventories of air pollutants for proposed metropolitan cities.[3] Technical infrastructure included wind profilers, radiometers, and wind lidar for continuous upper air observations.[3] The original SAFAR program budget requirement totaled 90.00 crores over the period 2012-13 to 2016-17, with allocations of 25.00 crores in 2012-13, 30.00 crores in 2013-14, 20.00 crores in 2014-15, 10.00 crores in 2015-16, and 5.00 crores in 2016-17.[3]

Benefits and Impacts

The forecasting system provides AQI forecasts similar to weather warnings, which Mumbaikars had not previously been able to access.[5] The forecasts are expressed in anticipated hourly levels of PM2.5 and PM10, and an accompanying map provides users with a spatial and temporal distribution of air pollution across the larger MMR area over the next few days.[5] MPCB officials stated that before winter, when the city's AQI usually worsens, having more stations in place would enable better monitoring and identification of areas which record poor AQI and allow for mitigation accordingly.[6] The expanded monitoring network provides better ground-level reporting that helps identify local pollution sources.[2] The Mumbai Climate Action Plan created a detailed climate profile and vulnerability assessment using satellite imagery, identifying areas and parameters at most risk, ranging from mapping mean surface temperature, vegetation cover, water connection prevalence, to pollutant concentration and flood prone areas.[7]

Climate Adaptation Relevance

The air pollution forecasting system addresses climate adaptation needs by enabling proactive responses to air quality deterioration events that can be exacerbated by climate conditions such as temperature inversions and changing wind patterns. The system's ability to provide ward-level granularity allows municipal authorities to implement targeted emergency response measures in vulnerable neighborhoods before pollution episodes intensify. The integration of meteorological forecasting with air quality modeling supports climate-informed public health protection strategies.

Business Analysis

The objective of developing SAFAR in major metropolitan cities of India including Delhi, Pune, Chennai, Kolkata, Mumbai, Bangalore, and Hyderabad falls under studies of Atmospheric Chemistry and Climate.[3] IITM coordinates and leads the effort for the development of the SAFAR system and continues its effort in improving the skill of forecasts.[3] The deliverable is to develop and dedicate the System of Air Quality Forecasting & Research (SAFAR) to the nation as an operational service in at least 6 metropolitan cities.[3] The plan of augmenting the number of monitoring stations is part of a larger project where more than 50 monitoring stations are intended for installation across Maharashtra.[6] At present, only two stations are operational in Thane (Kasarvadavali and Upvan Fort) while there is one each in Bhiwandi (Gokul Nagar), Kalyan (Khadakpada), Ulhasnagar (Siddhi Vinayak Nagar), Virar (Vilanj), and Mira Bhayander (Bhayander West) areas.[6] The capital-intensive nature of CAAQMS stations at Rs 9 crore each requires sustained government funding commitments.[1][6] The operational model relies on multi-agency coordination between IITM, MPCB, and MCGM, with IITM providing technical expertise and forecasting capabilities while state and municipal agencies manage monitoring infrastructure and enforcement actions.[4]

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