New Delhi, October 10: The national capital's air quality was recorded in the higher end of the 'moderate' category on Saturday, but a government forecasting agency said it is likely to improve marginally on October 11.

The city's 24-hour average air quality index (AQI) stood at 197, which falls in the higher end of the 'moderate' category. It was in 'poor' category at 204 on Friday.

An AQI between 0 and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', and 401 and 500 'severe'. Delhi's Air Quality Continues to Remain Under 'Poor' Category.

The Ministry of Earth Sciences' air quality monitor, SAFAR, said PM 2.5 is the lead pollutant in Saturday's AQI and is likely to improve to the 'moderate' category by Sunday.

"The overall Delhi AQI is in the higher end of 'moderate' and at the edge of the 'poor' category, with PM2.5 as the lead pollutant," SAFAR said. It said the AQI is forecasted to marginally improve but remain in the 'moderate' category for tomorrow while further AQI is forecasted to improve by October 12, which will also remain in the moderate category.

It said the low pressure formed over the Bay of Bengal is likely to intensify to depression and move west northwestwards and influence the circulations in the north and central India.

"A shift in Delhi surface wind direction, northwesterly to southeasterly by October 12 is forecasted. This could influence air quality positively in the coming week," it said.

Due to stubble burning around Punjab, Haryana, and neighbouring border regions, the fire count was found at 253 on Saturday, SAFAR said. Starting October 15, stricter measures to fight air pollution will also come into force in Delhi and its neighbourhood as part of the Graded Response Action Plan, which was first implemented in Delhi-NCR in 2017. These measures include increasing bus and metro services, hiking parking fees and stopping use of diesel generator sets when the air quality turns poor.

When the situation turns "severe", GRAP recommends closure of brick kilns, stone crushers and hot mix plants, sprinkling of water, frequent mechanised cleaning of roads and maximising power generation from natural gas. The measures to be followed in the "emergency" situation include stopping entry of trucks in Delhi, ban on construction activities and introduction of the odd-even car rationing scheme.