NEW DELHI: As a gray blanket of smog smothered town and Delhiites struggled to breathe, air air pollution knowledge went lacking for a serious portion of Monday. Since 1 pm, neither hourly air high quality index (AQI) updates nor town’s each day common had been launched until late night, even because the air visibly worsened for the reason that afternoon.Whereas hourly AQI knowledge for particular person stations was again on the Central Air pollution Management Board web site round 9pm, there have been gaps in readings at a number of screens. There was no response from CPCB or the Fee for Air High quality Administration (CAQM) to TOI’s queries on the info outage.As per an impartial evaluation, the typical PM2.5 focus from 12am to 9pm on Monday was 249 micrograms per cubic metre as in comparison with 215 micrograms per cubic metre over the identical interval of the day before today. Primarily based on these readings, the PM2.5 ranges have been close to extreme on Monday.Until early afternoon, when the final obtainable readings have been revealed, town’s common PM2.5 ranges – the first pollutant liable for Delhi’s foul air – have been practically an identical to these recorded on the similar time on Sunday. But, the corresponding AQI values have been considerably greater, mirroring the palpable deterioration that residents might really feel.By night, visibility had dropped sharply and an acrid stench hung within the air. Roads and flyovers disappeared right into a yellow-grey haze as individuals lined their faces and hurried indoors.“The CPCB has not up to date any knowledge for the reason that afternoon and it is not the primary time this has occurred within the final two years. The information lacking from such a vital web site at such a essential time, handicaps residents, researchers and regulators in taking motion to scale back air pollution or provoke precautionary measures,” mentioned Sunil Dahiya, founder and lead analyst, Envirocatalysts.From 1pm onwards, knowledge went lacking from the CPCB web site however was obtainable on the DPCC portal. This indicated that the screens have been working and the glitch was elsewhere.By round 5.30pm, out of 562 stations throughout India, solely 4 have been reside.Gurgaon’s AQI ‘cowl story’: Bushes, partitions & lacking knowledgeA thick smokescreen hung over town until late Monday morning. It was a lot the identical in Delhi, Noida and different elements of NCR. However whereas Delhi’s AQI was 345 (very poor) and Noida’s 318 (very poor), Gurgaon appeared to be respiratory simpler with an AQI of 221 (poor). What one noticed did not match with what the info prompt.It has been like this via this peak air pollution season, since Diwali, with Gurgaon’s common AQI largely higher than different NCR cities. Since Diwali, Gurgaon has recorded solely two very poor AQI days, 16 poor days and three average days.Inside the similar airshed, this will occur generally due to wind route and hyperlocal meteorological components. However when it sustains over a time frame, one has to look extra intently on the knowledge. In actual fact, place recording the info. That is what we did on Monday. It was revealing.All 5 steady air monitoring stations – at Vikas Sadan, Sector 51, Teri Gram, Gwalpahari and Manesar – are near thick foliage or close to partitions, violating CPCB guidelines that require screens to be put in not less than 20-30 metres from timber and 50 metres from main buildings, in open and well-ventilated areas. The stations have additionally not constantly recorded PM2.5 and sulphur dioxide (SO₂) knowledge, reducing town’s AQI averages. Gwalpahari and Teri Gram recorded incomplete indices for a number of days. LED show boards in any respect 5 stations have, in the meantime, been non-functional for weeks.Over time, vegetation inside govt and institutional campuses has grown tall round these stations, trapping air and absorbing a share of pollution earlier than they attain the sensors. The atmosphere of the stations, in different phrases, could be very totally different from the atmosphere of the street that hits you as you step out. “Vegetation grew, however the screens’ areas stayed fastened,” an official mentioned.An evaluation of CPCB’s real-time knowledge reveals the Gwalpahari station did not report PM2.5 ranges for a number of hours on a number of days this month. Since AQI averages are based mostly on obtainable readings, lacking knowledge of PM2.5 – the pollutant most liable for NCR’s poor air – improves the typical rating. At Teri Gram, SO₂ knowledge was lacking for prolonged durations, which implies one key gaseous pollutant wasn’t factored in AQI calculations.“The stations are recording partial knowledge and AQI seems higher than it ought to. There are lengthy gaps in knowledge,” mentioned Shubhansh Tiwari, a analysis affiliate at Centre for Science and Setting.“There is no such thing as a reside show, however the knowledge is being generated every single day. LED screens are unable to point out knowledge as they have been shut down for a number of months,” Krishan Kumar, regional officer, HSPCB, instructed TOI.