Chennai: As the city braces for Diwali firecracker smoke, residents have few ways to check how bad the air is. One of the state’s nine monitors has gone blank, and the city corporation’s ₹6.2 crore sensor network does not display Air Quality Index (AQI).While cities such as Delhi, Bengaluru, Mumbai, and Hyderabad have more than 15 continuous ambient air quality monitoring stations (CAAQMs) relaying real-time data to the public, Chennai’s number of AQI readers has been reduced to eight.On Friday, the Central Pollution Control Board (CPCB) website provided AQI and pollutant levels from only eight stations. Alandur station had no data. Data on nitric oxide (NO) pollutants was missing from the Velachery station.A senior TNPCB official admitted that not all monitors were functioning and that the annual maintenance contract renewal for CAAQMs was underway. “These continuous monitors cost more than ₹1 crore a piece, and lakhs for maintenance. We plan to float a tender for maintenance of these stations,” the official said. “Work is underway to set up 80 low-cost sensors across the state costing ₹6 to ₹8 lakh a piece. The accuracy may be less, but data will be more representative of a region,” the official said. However, the new monitors won’t be available until next year.Greater Chennai Corporation’s (GCC) monitors are also faulty. They were set up at 75 locations at a cost of ₹6.2 crore. They show several parameters but not AQI. More than 40 are inside school premises, so the public cannot see them.Some of the data displayed were wrong too. “The rainfall data always shows as 0. Humidity levels are the same on most days, and no one has followed up for maintenance even a month after installation,” a school headmaster said. No monitor had been installed at Thazhankuppam in Ennore, though GCC data claims a sensor is working there.The monitors are connected to the Integrated Command Control Centre (ICCC) at the GCC. Nodal officer G Rajeswari admitted that the sensors had to be recalibrated. “Though we intended to track only AQI and noise initially, we are now tracking more parameters, including wind speed, direction and pressure, besides AQI. All this data is relayed to the ICCC, but only some of it is made public,” she said, adding that the data would be studied and used for research.GCC commissioner G S Sameeran said the data can’t be made public this Diwali. “We are coordinating with the TNPCB, but there are no plans to release the data to the public at the moment. We are raising awareness to curb pollution,” he said.
