Mumbai: MPCB's battle for accurate air quality data in city intensifies

Amidst concerns over deteriorating air quality and rising worries about dust and pollutants, the Air Quality Index (AQI) recorded at the Andheri-Chakala air quality monitoring station in Mumbai has been consistently alarmingly high in recent days, causing widespread concern. The Maharashtra Pollution Control Board (MPCB) has challenged the accuracy of these readings and pointed to issues with the station's location.

The continuous ambient air quality monitoring station (CAAQMS) at Andheri-Chakala is established and managed by the System of Air Quality and Weather Forecasting and Research (SAFAR), a national initiative under the Indian Institute of Tropical Meteorology (IITM), Ministry of Earth Sciences (MoES), Government of India.

While all other stations under the purview of IITM/SAFAR and MPCB have been reporting AQI readings within the moderate to very poor range, the Andheri-Chakala station has consistently reported AQI values in the severe category (above 400 AQI) for the past few days.

Screengrab of the SAFAR and Sameer app showing the AQI levels

On Friday, the Central Pollution Control Board's (CPCB) SAMEER app displayed an AQI value of 423 for the IITM-run Andheri-Chakala station, while SAFAR's app reported a higher value of 560 for the same station.

Regarding these discrepancies, officials from IITM/SAFAR did not respond to text and email inquiries. V M Motghare, MPCB's joint director of Air Pollution Control, stated, "The Andheri-Chakala station is not functioning properly and has remained closed for the past year. Additionally, there is a large marble-cutting factory located adjacent to it. It is not our station."

Motghare shared the preliminary findings of the pollution control body's visit to the Andheri-Chakala station, saying, "The CAAQMS is situated on a soil playground where natural dusting occurs. Just behind the CAAQMS, a large marble-cutting operation is conducted at a distance of approximately 10 metres. The CAAQMS has not been opened for operations and maintenance (O&M) in the last year, and, as a result, no calibration has been carried out."

MPCB officials pointed out that the marble-cutting unit is in close proximity to SAFAR's Andheri AQI monitoring station, separated only by a wall. The dust generated by both the unit and the adjacent playground, where the station is located, inevitably contributes to elevated AQI values, as emphasized by MPCB officials.

Furthermore, officials have noted that SAFAR's CAAQMS installations are strategically placed in areas with higher traffic-related emissions compared to other locations. In the case of the Andheri station, pollution from both the playground dust and the nearby marble-cutting unit significantly contributes to air pollution, rendering this setup unsuitable for providing an accurate representation of overall air quality.

This isn't the first instance where MPCB has questioned the accuracy of AQI readings at its air monitoring stations and their locations. In January of this year, the state's principal pollution control and regulatory authority initiated a request to relocate the nine monitoring stations administered by SAFAR. The rationale behind this move was the belief that these stations did not accurately reflect the ambient air quality of Mumbai.

A meeting was held between MPCB and the Brihanmumbai Municipal Corporation (BMC) on January 12, during which MPCB formally presented their request to relocate SAFAR's monitoring stations. SAFAR's monitoring stations are currently located in BKC, Chembur, Worli, Colaba, Bhandup, Andheri, Borivli, Malad, Mazgaon, and Navi Mumbai.

Additionally, officials highlighted that SAFAR's CAAQMS installations are positioned in areas characterised by higher traffic-related emissions compared to other locations. Consequently, this configuration does not provide an accurate representation of overall air quality. In the case of the Andheri station, pollution from both the playground dust and the nearby marble-cutting unit significantly contributes to air pollution.

This suggestion by MPCB in January not only strained the relationship between the pollution control body and IITM officials but also sparked a debate among various stakeholders.

Apart from the nine SAFAR monitors, MPCB operates at least 11 CAAQMS in Mumbai. These stations generally report lower pollution levels in terms of AQI compared to SAFAR's monitoring stations.

Countering MPCB's allegations and defending SAFAR, senior scientist and former project director of SAFAR, Dr Gufran Beig, said, "The CAAQMS has been set up and run by SAFAR since 2015. All nine stations have been established following international guidelines framed by the World Meteorological Organization (WMO). WMO has issued clear and detailed guidelines for setting up CAAQMS, including the number of stations needed in proportion to the city's or area's population and their optimal locations."

Beig added, "There have been no problems or complaints about these stations from 2015 to 2021. The problem suddenly began after 2021 when the AQI in the city started deteriorating. The stations should be placed in areas that accurately represent the city and are clean and green. If the current locations of the SAFAR stations do not accurately represent Mumbai's ambient air quality, will relocating them to gardens and cleaner places provide more accurate readings?"

According to sources at IITM, none of the SAFAR stations are closed or out of operation, and they continue to provide accurate readings.

560
AQI value on Friday reported by SAFAR's app

400
AQI value after which air is reported in the severe category