london has a live tracker measuring each breach of hourly levels of toxic nitrogen dioxide and is accordingly shifting clean buses onto the most polluted routes and delhi has tried out everything from bans to fines but chennai lags behind at least by a decade in terms of mechanism to track pollution and government policies to control itthe tn pollution control board tnpcb has three continuous monitoring stations in koyambedu kodungaiyur and royapuram that are operated twice a week that too on a rotational basis the data generated is then sent for validation to a usbased firm with laboratories in hyderabad a week later the validated data is released on the tnpcb website since there are variations while collecting data validation is mandatory to ensure precision say tnpcb officials the validation may sometimes take a week to a fortnight and the website update is not always regularthere are also manual stations in adyar ambattur t nagar nungambakkam kilpauk tiruvottiyur manali and kathivakkam said a pollution control board engineer according to pcb officials while the continuous monitoring stations can be calibrated to monitor fine particulate matter with a radius of 25 micrometres pm25 levels that are generated mostly due to vehicular and industrial pollution the manual stations only monitor pm10 levelsin 1989 the industrial belt of manali kathivakkam and tiruvottiyur got the first air quality monitoring station in the city the second set of stations became operational eight years later in five more spots these stations initially monitored ambient air quality for eight hours starting from 8am only in 2002 they were made continuous monitoring stations approved by the united states environmental protection agency when asked whether the board has any plans to increase the number of monitoring stations in the city a senior official said they have no such plansthe city usually figures in the moderately polluted category with pm25 level hovering around 150 just below the safe limit of 200 but all it takes is a festival for the data to double and be on a par with delhi on january 14 the ritual of burning on bhogi triggered smog that delayed flights and reduced visibility to 50m near the airportcoordinator of healthy energy initiative india shweta narayan said it is astonishing that tnpcb is not monitoring air pollution real time as on january 28 data for january 24 was uploaded on the tnpcb website narayan points out that postdated data is of little use to the public because precautionary measures are impossible it seems tnpcbs exercise is a procedural monitoring with no practical purposes for festivals like diwali and bhogi it is real time data that would help people understand the impact what use is the data has if it is put out a week later questions narayan why is tnpcb lagging when delhi and even coimbatore employs realtime monitors and reporting mechanisms