Is Delhi’s AQI 500 or 1,500? The confusion is part of the problem

There are 2 salient points successful this regard. One, if upwind conditions and upwind levels are favourable for an intrusion from Punjab-Haryana and adjoining areas (around 500m to 1500m supra the surface) and they are accelerated capable to recede implicit NCT, past a threshold of adjacent 400-500 fires, combined with stagnation conditions (no dispersion) tin person an adverse section impact. Two, models amusement a heavy broad astatine 500m alternatively of wide skies. This is conscionable supra the bound furniture that separates the little ambiance from the inversion furniture above. This broad descends arsenic temperatures autumn astatine nighttime and is mostly liable for elevated contamination levels. However, successful the week starring up to November 18, contamination changeable up from sunrise until day erstwhile the bound furniture breaks and rises. That is due to the fact that the ominous broad of polluted aerial astatine 500m made a downward intrusion and worsened aerial quality. This suggests that determination is simply a large root of outer contamination arsenic section emissions volition not emergence truthful sharply. A operation of fossil fuels, home emissions and this chartless root person played havoc with Delhi’s air.

Given the world of clime change, determination are galore factors astatine play and they request multidisciplinary, multisectoral solutions. We are witnessing galore antithetic events — the warmest October connected record, uncertainty astir the onset of La Nina and more. La Nina, associated with a bully monsoon, was initially expected by June. We person witnessed a bully monsoon – and LaNina is yet to acceptable successful properly.

La Nina is important to the aerial prime treatment due to the fact that it is associated with amended upwind circulation – wintertime 2022 was a lawsuit successful point.

The aerial we respire is simply a prime we marque arsenic a nine astatine the disbursal of our wellness and that of young children. The aerial prime contented this clip has thrown up much questions than answers. We request to guarantee greater transparency connected specified an important matter. The top disorder was that immoderate credible backstage agencies often amusement AQI readings of much than 1,000-1,500 portion the authoritative fig ne'er goes beyond 500, utilizing the aforesaid information from the authorities. This is due to the fact that India’s guidelines for converting wide attraction of pollutants to the AQI figures are based connected its ain “breakpoint”, which are acold little stringent than the WHO-prescribed guidelines. Breakpoint is the threshold level from wherever the AQI readings spell from 1 class to another. Our AQI is acceptable based connected our epidemiological information and susceptibility studies that support the Indian situation successful mind. This would beryllium fine, but for the discomfort of mounting a headdress astatine 500 AQI, careless of however galore times the concentrations transcend that level.

Another superior contented emerged erstwhile a elder probe idiosyncratic from NASA claimed that farmers successful north-west India person changed the clip for stubble burning by 3-4 hours to debar detection by the MODIS instrumentality connected committee the Terra and Aqua satellites that walk implicit this area. These satellites are not geostationary – they lone walk the areas doubly successful 24 hours. This decision was based connected images from the Korean geostationary outer (GEO -KOMPSAT 2A) which, it was claimed, showed localised puffs/clouds of fume successful the precocious afternoon. I bash not privation to marque immoderate judgement connected the contented astatine this stage. However, to recognize the information astir the timing displacement scientifically, we should analyse and process the images of our Indian geostationary satellites (INSAT-3D/3DR), which supply continuous sum (every 15–30 minutes).

A important magnitude of enactment utilizing ISRO satellites is going connected successful India for assorted applications. Unfortunately, not overmuch attraction is paid to aerial prime successful this regard. This is 1 crushed our authoritative occurrence number information is babelike connected NASA satellites. We person the capableness of becoming autarkic successful this country and whitethorn adjacent motorboat a caller high-resolution satellite. But this requires a push. The Delhi aerial prime situation is simply a reminder to framework strategies by scientifically integrating aerial prime and clime factors and prioritising health-centric measures. This tin champion beryllium realised by a assets framework, arsenic envisaged precocious successful a stakeholder gathering convened by the bureau of the Principal Scientific Advisor to the Government of India.

The writer is Ashutosh Mukherjee Chair Professor, National Institute of Advanced Studies, Indian Institute of Science (IISc) Campus