The CPCB data showed that the PM10 (particles with diameter less than 10mm) level was beyond "severe" at 778 in Delhi-NCR area and 824 in Delhi particularly, leading to hazy conditions and limiting visibility.
Gufran Beig, a scientist at the centre-run System of Air Quality and Weather Forecasting and Research institute, said the dust storm deteriorated the air quality in Delhi-NCR.
"There was a ground-level dust storm in the western part of the country that increased drastically coarser particles in the air, causing a spike in pollution levels in Delhi," he said.
But the air quality should improve later today, he said.
According to CPCB, the air quality index at several places in Delhi crossed the 500-mark, with east Delhi's Anand Vihar area recording an AQI of 891.
An AQI between 0-50 is considered "Good", 51-100 "Satisfactory", 101-200 "Moderate", 201-300 "Poor", 301-400 "Very Poor", and 401-500 "Severe".
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