Delhi: Why India's Air Quality Reporting System Faces Criticism
In the bustling city of Delhi, the air is thick with a haze that lingers like a persistent fog, making the daily commute a challenging endeavor for many. As the sun rises, the air quality becomes a topic of concern for residents, who eagerly check their devices to gauge the severity of the pollution.
However, the numbers displayed on these devices can vary significantly, leaving people perplexed. Government-backed apps like SAFAR and SAMEER cap their readings at 500, adhering to India's Air Quality Index (AQI) scale. This scale, introduced over a decade ago, categorizes air quality into different levels, with readings above 400 deemed 'severe' and posing health risks to both healthy individuals and those with pre-existing conditions.
But here's the catch: private and international tracking platforms, such as IQAir and AQI, often reveal far more alarming figures, surpassing 600 and even reaching 1,000 on certain days. This discrepancy raises a critical question: Which numbers should residents trust?
The answer lies in understanding the origins of the 500 cap. When the National Air Quality Index was launched, it was assumed that the health impact of air pollution would plateau beyond a certain point, as the worst-case scenario had already been reached. Gufran Beig, the founder director of SAFAR, explains that the cap was initially set to prevent panic, as crossing 500 indicated an urgent need for mitigation measures.
However, this approach has its limitations. By capping the data at 500, official monitors overlook the severity of air quality beyond this threshold. International organizations and portals, such as those used by the World Health Organization (WHO), do not impose such caps, allowing for more accurate representations of pollution levels.
The discrepancy extends to the definition of hazardous air. The WHO guidelines classify PM2.5 levels above 15 micrograms per cubic meter over a 24-hour period as hazardous, while India's threshold is set at 60 micrograms. This variation in standards can lead to confusion and misleading comparisons.
Furthermore, the instruments used for monitoring play a crucial role. India's pollution control board employs Beta Attenuation Monitors (BAMs), which provide precise measurements of particle mass in the air, calibrated to strict, standardized metrics. In contrast, portals like IQAir utilize sensor-based monitors, which estimate particle counts using laser scattering and electrochemical methods.
Abhijeet Pathak, a former scientist at India's pollution control board, highlights the limitations of sensor-based monitoring, which has not yet been approved by the Indian government. He argues that India's air quality framework has not been comprehensively updated since 2009, and calls for recalibration based on the latest technology.
The debate over the 500 cap and the need for a revised AQI scale intensifies as the health implications of air pollution become increasingly evident. With pollution levels rising, experts emphasize the importance of removing the cap to accurately reflect the worsening air quality and guide public health measures.
