As Delhi air quality turns severe, GRAP Stage 4 curbs invoked

New Delhi: The Centre's air quality panel for Delhi-NCR implemented tough measures under Stage 4 of the air pollution management plan on Monday after the region's air quality became "severe" due to unfavourable weather circumstances, an official order stated. 

The winter limitations under Stage 4 of the Graded Response Action Plan (GRAP) include a prohibition on every construction and demolition activities, including public projects like highways and flyovers, as well as the entry of trucks carrying non-essential items into Delhi.

Delhi's 24-hour average air quality index, which was 379 at 4 pm, breached the 400 mark around 10 pm amid extremely calm winds and "buildup of an inversion layer adversely affecting the vertical mixing height".

Vertical mixing height is the height above the surface throughout which a pollutant can be dispersed.

With PTI inputs