Kamal Ghorui
New Delhi: Delhi Pollution Control Committee (DPCC) has made six new Continuous Ambient Air Quality Monitoring Stations (CAAQMS) operational, but they are yet to be integrated with Central Pollution Control Board’s (CPCB) network. As a result, the city’s air quality index (AQI) is currently being assessed using data from only 40 stations. After the new stations were announced last year, experts raised concerns that their locations in relatively greener areas could influence the city’s average readings. With DPCC beginning to share data from Monday, experts said only long-term monitoring will show whether the new stations impact Delhi’s overall AQI.
On Monday, Delhi’s average AQI — based on 39 of the 40 existing operational stations — stood at 228, falling in the ‘poor’ category. PM10 and ozone were recorded as the dominant pollutants. Sunil Dahiya, founder and lead analyst at think tank Envirocatalysts, said, “The readings of different pollution parameters of new stations are available, but they are yet to be integrated with CPCB. After we analyse the data of a few more days, we will be able to say if new stations are skewing the city’s average or not.” Dipankar Saha, former head of CPCB’s air laboratory, said monitoring stations must be evenly distributed across various land-use types to ensure representative measurements. “It is important to distinguish between background, impact and immediate-exposure monitoring stations, and to understand the area of influence of each location — something that is still unclear,” he said, adding, “While stations in green zones can be useful, all monitors must be placed in well-ventilated areas to ensure representative data for the city.” Among the six new stations, Delhi Cantonment recorded the highest pollution levels on Monday. At 4pm, hourly PM10 and PM2.5 concentrations there were 125 and 61 micrograms per cubic metre, respectively. The national daily limits are 100 micrograms per cubic metre for PM10 and 60 micrograms per cubic metre for PM2.5. The Commonwealth Sports Complex in Akshardham recorded the next highest levels, with PM10 at 116 micrograms per cubic metre and PM2.5 at 47 micrograms per cubic metre at 4pm. The six stations were inaugurated on Feb 9, taking Delhi’s total to 46. Another 14 stations are planned for the next financial year. Officials said the aim is to achieve full coverage using a 5x5km grid, ensuring one monitoring station for every 25 sq km.
