New Delhi's pollution reading can hit 500 on the Air Quality Index, last week it had a 38 reading

New Delhi's citizens 'can't believe' how quickly their city's air quality has improved during India's national novel coronavirus lockdown, The New York Times reports.

With people off the roads, flights grounded, and factories shuttered, New Delhi has experienced a remarkable turnaround when it comes to pollution. On bad days, the city's Air Quality Index — which measures different airborne pollutants — can register a reading of 500 or higher, essentially maxing out the scale. When that number hits 150, it's reportedly considered a good day. Last week, the AQI was at 38.

https://theweek.com/speedreads/907597/new-delhis-pollution-reading-sometimes-hit-500-air-quality-index-last-week-recorded-reading-38