NEW DELHI: Air quality in the national capital dipped towards 'poor' zone on Friday. Scientists and officials said the present deterioration, while good winds are still blowing over Delhi, is mainly on account of pollutants from farm fires in neighbouring states.
However, with a forecast of rain over the weekend, air quality is likely to remain in check till October 20.
As per the Central Pollution Control Board (CPCB) data, on Friday, Delhi's overall air quality index (AQI) was 198, just three digits away from the 'poor' mark. Though still in the 'moderate' zone, it's just short of entering the 'poor' zone, as most of the 36 monitoring stations in the city are in the 'poor' category.
Last time Delhi saw poor air quality this year was on July 2. An AQI reading of 201-300 is considered 'poor' while 301-400 is ‘very poor’ and 401-500 is 'severe'.
Forecasters said that so far northwesterly winds have been blowing over the city bringing in pollutants from stubble burning in neighbouring Punjab and Haryana. However, the wind direction will change to easterly from Saturday.
"The wind direction is likely to switch to moisture-laden easterly winds, which may result in rain or thundershowers in the northwest region including Delhi. Under such weather, the night temperature rises and the day temperature drops, which is favourable for dispersion of pollutants. Also, showers are expected to wash away the pollutants," said a senior IMD official.
The air quality is likely to improve over the weekend and remain in check till at least October 20. From October 21, when night temperature is expected to drop and northwesterly winds are likely to return, the air quality may deteriorate, the official added.
A senior Delhi Pollution Control Committee (DPCC) official said the change in the weather conditions combined with fumes from stubble burning is the major reason behind the annual spike in pollution. The Commission for Air Quality Management (CAQM) will be reviewing the air quality to decide whether emergency measures are to enforced at present or not.