New Delhi: Delhi’s air quality improved further on Tuesday, giving respite to people suffering from acute pollution for a week. The trend is likely to continue for a couple of days.

The air quality index (AQI) dropped from 365 at 9.45 am to 331 at 3.45 pm, according to the Central Pollution Control Board.

The National Capital Region (NCR), Greater Noida (348), Noida (358), Ghaziabad (351), Faridabad (311), and Gurgaon (328) also recorded improvement in air quality.

An AQI between 0-50 is considered ‘good,’ 51-100 ‘satisfactory,’ 101-200 ‘moderate,’ 201-300 ‘poor,’ 301-400 ‘very poor,’ and 401-500 as ‘severe.’ An AQI above 500 falls in the ‘severe plus’ category.

The India Meteorological Department (IMD) said that winds gusting up to 25 kmph are flushing out pollutants faster.

“There are good chances of rain in Northwest India on Wednesday night and Thursday due to a western disturbance. The precipitation will cover Delhi-NCR, Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Punjab, Haryana, Rajasthan, and western Uttar Pradesh,” said Kuldeep Srivastava, the head of IMD’s regional weather forecasting centre.

He said the situation will not be similar to that of Sunday, when high humidity due to light rains led to the formation of more potent secondary particles.

Secondary particles are products of complicated atmospheric reactions between primary particles—such as particulate matter, sulphur dioxide, and nitrogen dioxide directly emitted by stubble burning and vehicles — in the presence of other factors such as sunlight and moisture.