Delhi breathed easier on Thursday morning as pollution levels dropped further due to moderate wind speed. The air quality index in the national capital dropped to 235 at 6:30 am. The Ministry of Earth Sciences' air quality monitor, SAFAR, said, "The AQI is back to 'poor' category due to a change in the wind direction. Safar added that the share of stubble burning in Delhi's pollution dropped to a meagre 3 per cent.
SAFAR said, "A change in the wind direction has led to a very low biomass plume intrusion in spite of the fact that the fire count observed yesterday was very high."
Delhi's overall air quality index improved significantly (from very poor to poor) on Thursday, more rapidly than predicted. The PM 2.5 -- tiny particulate matter less than 2.5 microns in diameter that can enter into the lungs and event the bloodstream -- and PM 10 levels also dropped.
Gurgaon recorded 'moderate' AQI, while Faridabad, Noida and Ghaziabad recorded 'poor' overall 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 severe. Above 500 is severe-plus emergency category.
The AQI of four places in and around Delhi has been provided in the table given below.
Delhi Chief Minister Arvind Kejriwal said he was glad to see that pollution levels had come down, but efforts have to be made to ensure there is no increase.
The Delhi government has introduced the third edition of odd-even scheme as part of anti-pollution measures. The the 12-day road rationing rules had come into effect on November 4.
The Supreme Court-mandated Environment Pollution (Prevention and Control) Authority had on Monday extended the restrictions on hot mix plants, stone crushers and dirty fuel-based industries in Delhi-NCR till the morning of November 8 expecting a repeat of Sunday's episode.
The Supreme Court had also banned construction activities in Delhi-NCR till further orders.
On Sunday, pollution level in Delhi peaked to a three-year high as high humidity due to light rains on Saturday led to formation of more potent secondary particles.