New Delhi, Sep 22 (PTI) Farmers in Punjab and Haryana have started burning crop residue, but its impact on Delhi's air quality will be minimal for the next three days, according to the Ministry of Earth Sciences' air quality monitor, SAFAR.
Satellite imagery from space agency National Aeronautics and Space Administration (NASA) have also shown that farmers have started burning crop residue in parts of Punjab and Haryana.
According to an estimate based on satellite data, the farm fire counts were 42 on Monday, 20 on Sunday and nil on September 15, the System of Air Quality and Weather Forecasting And Research (SAFAR) said.
'Though stubble burning has started in Punjab and the neighbouring border regions, its impact on Delhi's air quality index will be minimal for the next three days since the predominant winds are not supportive for transport and accumulation,' it said.
The predominant, non-supportive wind direction is north-easterly.
On Tuesday, the national capital recorded an air quality index of 115, which falls in the moderate category.
According to SAFAR, the contribution of farm fire smoke in Delhi's pollution peaked to 56 per cent in 2018 and 44 per cent in 2019.
It is a bumper harvest this year. So, the incidents of stubble burning might go up, an official of the Punjab Pollution Control Board said.
'We have been providing machinery to farmers for in-situ management of crop residue, but stubble burning is a traditional practice. It takes time to bring a change in the mindset,' an official said.
On August 31, the city recorded a 24-hour average air quality index of 41, which was the lowest since the Central Pollution Control Board started maintaining air quality records in 2015.
It was the fifth 'good' day in terms of air quality this year.
AQI values were 45, 50, 50 and 45 on March 28, August 13, August 20 and August 24, respectively. The AQI value remained between 50 and 70 on most days in August.
A CPCB official said the improvement in air quality was due to favourable weather -- good wind speed and rainfall and curbs due to the COVID-19 pandemic.
However, the AQI slipped into the moderate category in September due to lack of rains which wash pollutants away.
An AQI between 0 and 50 is considered safe, 51-100 satisfactory, 101-200 moderate, 201-300 poor. At 301-400, it is considered very poor and 401-500 falls in the severe category. The above 500 is severe as well as the emergency category. PTI GVS NSD NSD