As a thick blanket of haze and dust enveloped Delhi and parts of the National Capital Region (NCR), the air quality nosedived to the "severe" level.
The current increase in levels of pollution is mainly due to drastic increase in coarse particles in air which has caused a spike in PM10 level, it said.
The CPCB, however, said the pollution of this season was different from November last year when both PM2.5 and PM10 had spiked.
The Environment Ministry has attributed the dusty conditions to an upshot of dust storms from Rajasthan.
The dust in the air isn't allowing the gruelling heat to escape.