Delhi’s air quality improved on Wednesday following overnight rain that washed away bigger pollutants, PTI reported. Stubble burning in neighbouring states also declined and contributed only 3% to pollution in the national Capital on Wednesday, the lowest this month.

The air quality index at 7 pm was 293, in the “poor” category, according to the Central Pollution Control Board. It had remained in the “very poor” category for most of the day. For the past one week, the air quality had been under “severe” category.

At least 21 areas in Delhi recorded “very poor” air quality, while 14 showed “poor” air quality, CPCB said. Faridabad, Greater Noida, Noida and Ghaziabad in the National Capital Region recorded “very poor” air quality, while in Gurgaon, the air quality was recorded in “poor” category.

In Delhi, the PM2.5 level – particles in the air with a diameter of less than 2.5 micrometres – on Wednesday was at 175 and PM10 level was at 280, according to System of Air Quality and Weather Forecasting And Research, or Safar.

“Stubble fire is unlikely to impact Delhi air quality index as fire counts are significantly down and winds are also flowing from other direction,” SAFAR said in a report.

Meanwhile, the Supreme Court-appointed Environment Pollution Control Authority lifted the ban on the entry of heavy vehicles into Delhi on Tuesday. The agency said heavy vehicles would now ply in the city between 11 pm and 6 am.

Delhi’s Environment Minister Imran Hussain said he was studying the authority’s proposal to ban private and commercial vehicles that do not use compressed natural gas if the air quality does not improve.

More than 2,200 vehicles were asked to turn back from the national capital’s borders when restrictions were imposed between November 8 and November 12 in the wake of high pollution levels. Only vehicles carrying essential goods were allowed entry.