New Delhi: The national capital has experienced poor to severe air quality for a total of 398 days out of 703 days, over a period of three years, according to the Central Pollution Control Board.

In 2018 (till August 26), poor to severe air quality was observed for 120 days, while in 2017 it was 125 days and in 2016 it was 153.

The total number of days considered for the analysis were 227 in 2016 and 238 each in 2017 and 2018, the official added.

Moreover, reasons at local level were listed as biomass burning, secondary particulates, vehicles, coal and fly ash, road and soil dust.

At regional level, the pollution causing factors were stubble burning in Haryana and Punjab, while at the global level the pollution causing factors are transboundary dust storms and stubble burning.

The CPCB also listed out the approach it was adopting for the upcoming winter season.

Some of the measures include field inspections by the CPCB, decentralised management of air quality — a micro level action plan, linking micro level action plan of various agencies, implementation of the Graded Response Action Plan in Delhi and NCR towns, a CPCB official told reporters.

The measures also included formation of expert committees and panels and follow-up with agencies for directions, the official said.

(Inputs from PTI)