Delhi-NCR pollution: Slight improvement in air quality due to strong winds

Air pollution in Delhi ameliorated marginally on the back of strong winds on Saturday but farm fires raging in Punjab prevented a significant improvement in the air quality.

Delhi's 24-hour average air quality index (AQI) stood at 303 on Saturday, improving from 346 on Friday. It was 295 on Thursday.

An AQI between 201 and 300 is considered "poor", 301 and 400 "very poor", and 401 and 500 "severe".

Officials at the India Meteorological Department (IMD) said winds gusting up to 18-20 kmph barrelled through the city during the day, improving air quality and visibility levels.

The Centre's air quality panel had on Friday said curbs under stage 3 (severe) of the Graded Response Action Plan (GRAP) will continue in Delhi-NCR as the air pollution in the region is showing an upward trend.

All construction and demolition work, except for essential projects, is banned in Delhi-NCR under the third stage of the GRAP. Brick kilns, hot mix plants and stone crushers are also not allowed to operate.

The commission noted that north-westerly wind flow is conducive for an increase in the impact of farm fires on the capital's air quality.

According to data from the Indian Agricultural Research Institute (IARI), farm fires in Punjab dipped from 3,916 on Friday, the highest this season so far, to 2,467 on Saturday.

Their share in Delhi's PM2.5 pollution also declined from 19 per cent on Friday to 17 percent on Saturday, according to SAFAR, a forecasting agency under the Ministry of Earth Sciences.

However, the data from the Decision Support System of the Indian Institute of Tropical Meteorology showed that "biomass burning" was the top contributor to air pollution in Delhi-NCR on Saturday.

With air pollution ameliorating in Delhi, the CAQM had on Sunday directed authorities to lift the curbs imposed under stage 4 of the GRAP, including a ban on plying of non-BS VI diesel light motor vehicles in the region and the entry of trucks into the national capital.

The CAQM order recommending the restrictions was issued on Thursday.

The Delhi government had also shut primary schools and ordered 50 per cent of its staff to work from home last week.

However, the directions were rescinded following an improvement in air quality.

According to an analysis conducted by the Delhi Pollution Control Committee last year, people in the national capital breathe the worst air between November 1 and November 15 when stubble burning peaks and winters set in.

The Air Quality Life Index (AQLI) released by the Energy Policy Institute at the University of Chicago in June showed that residents of Delhi stand to lose 10 years of life expectancy due to poor air quality.