Awaaz Foundation flags faulty AQI monitors at Mumbai construction sites, seeks BMC action

Awaaz Foundation has raised concern over alleged irregularities in the readings of air quality index (AQI) monitors installed at construction sites in Mumbai. The foundation has written to the BMC commissioner and the Chief Minister of Maharashtra, demanding an immediate inquiry.

The foundation checked the displays at six to seven construction sites in Bandra and Khar 230 times over 38 days. The readings were compared with those of nearby monitoring stations.

Monitoring was carried out in two rounds, the first between March and May and the second between September and October. From March 23 to May 5, the foundation noted the readings on boards outside construction sites and compared them with readings from the Central Pollution Control Board (CPCB) stations at Kherwadi and BKC.

According to the foundation's report, the PM2.5 level showed zero on some boards. On several occasions, when the CPCB monitors showed higher levels, the site boards still showed PM2.5 and PM10 in single digits. Some boards showed question marks or dashes instead of readings. In September and October, the foundation compared the construction site readings with AQI (US), which it said were considerably higher.

Sumaira Abdulali of Awaaz Foundation wrote, "PM2.5 is dust so fine that it reaches the lungs and the blood. These displays are meant to warn the people who live here, and no one is accountable for them."

The foundation has asked the civic body to calibrate and audit the monitors at every construction site, and to put real-time, time-stamped PM2.5 data online. It has also demanded a separate website for live readings, the deployment of air pollution monitoring vans, and action against faulty display boards.

Abdulali wrote, "We know that the BMC has said it will add the readings of these site monitors to its official findings, so that local data becomes part of the picture of the city's air. We welcome this intent. But unless the data is first verified with calibrated meters, this exercise will be meaningless."

She said people rely on local display boards to decide whether to go out or let children play, and wrong readings can mislead people worried about pollution.

When contacted, Additional Municipal Commissioner Avinash Dhakane said monitors at open construction sites can develop faults. He said the corporation's dashboard keeps track of the data and officials have been instructed to get faulty monitors repaired within three days.

Dhakane said, "In any case, ambient AQI and these low-cost sensors are not comparable with each other. The purpose of the construction site sensors is to help the BMC with 'hotspot monitoring'. When boards at several construction sites in the same area show high figures, our officers intervene immediately. AQI in Mumbai is being recorded between 100 and 120, which is moderate." He also said the BMC is working on adding artificial intelligence to the dashboard to catch such cases automatically.

Among the cases recorded in the report, PM2.5 was shown as zero near Pali Hill on April 13. On April 24, both PM2.5 and PM10 showed zero near Pali Hill.