Air back in 'very poor' zone as wind speed slows down

Delhi's air quality index (AQI) surpassed the "very poor" mark of 300 on Saturday, a significant deterioration from the 261 (poor) recorded a day earlier. Experts said a weakening of winds over the region was behind the jump in air pollution and any improvement can only be expected after October 31 (Tuesday).

Northwesterly winds have temporarily been replaced with those from the southeast, which are weaker and are thus leading to dust, industrial emissions and tailpipe gases to be trapped closer to the ground.

"The winds are calm at night due to which dispersion of pollutants is poor and we see a dip in air quality," said India Meteorological Department (IMD) scientist Kuldeep Srivastava.

According to the 4pm bulletin of the Central Pollution Control Board (CPCB), some of Delhi's satellite cities had better air quality: AQI was 291 in Ghaziabad, 252 in Gurugram, 272 in Faridabad and 286 in Noida.

Delhi and the larger national capital region (NCR) covering these areas are in the middle of a sensitive window when air quality typically plummets to levels unfit for breathing in. A large contributor to that problem is smoke from farm fires in Punjab and Haryana, where farmers tend to burn the stubble left after paddy cultivation as an inexpensive and quick method to clear their fields.